Email clients that for whatever reason allow sending HTML email typically default to sending multipart messages with a normal plain text version as well. Emails that are HTML-only are typically marketing or unsolicited noreply junk.
I normally browse with a browser that doesn't even support JS (Lynx, NetSurf, or Dillo). Glad to know that anyone who doesn't use a browser developed by a company running on billions of dollars a year is just being "silly".
If I am compelled to use a "modern" browser, I turn off JS, cookies, remote fonts, WebGL, and any third-party resources and enable them on a case-by-case basis if the website is important enough (it usually isn't). Most sites worth visiting work much better when I do this.
I have Javascript off by default and only turn it on (using NoScript extension) whenever it's actually needed.
Most pages load just fine without and with those that don't it's a 50/50 between me enabling JS for it or deciding I didn't wanna view the content anyways and closing the tab.
As someone else mentioned it's not to deprive myself of functionality, but to deprive the vultures (trackers and other shady stuff) of it.
At one point I might have agreed with you, but after working on a few sites of my own I found that Javascript just enables a vastly better user experience. No need to refresh the page every time the user does something like liking a post or sending a comment, can load content more seamlessly with pre-loading or lazy loading, enables expandable menu bars to maximize space for content when the menu's not in use, things can be loaded faster and with less data usage if you send page diffs instead of full pages of markup, etc.
Javascript's terrible when it's used to generate pages from bloated frameworks that create 5000 DOM elements, add listeners to everything, load a dozen external scripts, and so on, but it's really valuable when used to actually improve the user experience.
Like you can probably guess, people tend to disable JS not because it can technically enable a good user experience.
Rather, they do so because it enables a majority of websites, and this includes big names like news websites, to create an absolutely horrible user experience - even if, or seemingly because, the content profits in no way from JS.
If you have ever tried to surf on an older laptop recently, you will get what I mean.
Everything you described can be done with progressive enhancement.
Only three engines exist that work well with JS; if we want our sites to not be dependent on behemoths like Google and Apple (Google is Mozilla's income source), we need to build sites that don't depend on their software (Blink, Webkit, and Gecko). That typically means not requiring JS.
People who block JS do so for good reason: when they open your site, they have no reason to believe that the JS being served isn't malware. If they disable and inspect it, they have no reason to believe that the scripts won't change the next time they open your page. It's safer to just leave it disabled.
For security plain text is best. US Federal Government Recommendation is to disable html:
“Organizations should ensure that they have disabled HTML from being used in emails, as well as disabling links. Everything should be forced to plain text. This will reduce the likelihood of potentially dangerous scripts or links being sent in the body of the email, and also will reduce the likelihood of a user just clicking something without thinking about it. With plain text, the user would have to go through the process of either typing in the link or copying and pasting. This additional step will allow the user an extra opportunity for thought and analysis before clicking on the link.”
That said theres another post on the front page about an Apple mail zero click exploit involving attachments so even plain text can’t dodge everything.
I think this is, aside from the security concerns, why many chat applications, forums and tools like Github/Gitlab have switched to standards like Markdown for text formatting.
I can see the value in linking, embedding images, highlighting through bold and italic text, and underlining. Even code can be useful inside an email. Markdown or a similar language would serve most people very well, much better than HTML. Non-automated and fully automated emails can do with a strong simplification.
Of course, marketing companies will always prefer full HTML because it allows for making their spam more gaudy and for making their emails follow their brand, usually through terrible abuse of tables and CSS that in the end only make emails unreadable on mobile, with dark mode enabled, or massively confuse screen readers.
If emails were written and parsed as markdown, I might (!) change my opinion about it. But HTML is vastly too feature-rich to be sane. I think showing images inline (such as in Github-flavored Markdown) is still too feature-rich. But lists, tables, monospaced blocks, italic, bold ... these are fine. Embedded images aren't conducive to being parsed by a script.
Inline images are very useful for diagrams, sharing screenshots and more. I can do without the stupid company logo underneath every email, but I'd much rather have to put up with those than be unable to use them. The resources need to be small enough to embed inside the email, though, and external resources should be made aa difficult as possible (always hidden by default, per rfc, with at least two clicks before they're displayed).
My perfect world email markdown will probably be different from yours. For productivity, anything more than slightly stylised text is just unnecessary, but in practice, most email isn't used for productivity anymore. Instant messaging has replaced email as a means of conversation in all workspaces I know.
"Free" antivirus software, Windows 10 telemetry, Javascript, WeChat, WhatsApp, Google Chrome, Gmail, Facebook, and countless other software choices are used by millions of people today; that doesn't mean that feeling uncomfortable conforming to the norm is unwarranted.
The millions of people you refer to probably (without realizing) send multipart messages with a plaintext version available. Emails without this are typically spam.
As someone who lies in Excel, Outlook and too many different chat apps I think it’s far too useful to have proper formatted text in communications -
Even very simple things like highlighting, tables, screenshots just don’t work or are unclear if you limit yourself to plain text.
Marketing emails can be annoying but that’s what the unsubscribe button is for ;)
Cynically, the unsubscribe button is so phishing operations spamming every possible permutation of {<plausible name>, <separator>}@<popular_service>.com can confirm they hit a real email address and spam it out to all the various constant contact subscribers that pay them for leads.
We have asterisks for emphasis , attachments for screenshots, and bulleted lists for a subset of tables. More complex tables and formatting probably work better in an attachment; the message body should be clear, concise, and render correctly in the recipient's mail client. When the body contains complex HTML, there's a good chance it'll render incorrectly in someone else's client.
Allowing fewer features is a feature in itself: when we try to allow everything without thinking about the consequences, we end up with something like the modern Web or Electron apps.
Proper formatted text in communications is fine -- include it as a separate attachment that's not automatically loaded and displayed instead of plain text.