By the time you are on the last 2 versions of popular browsers, you’re at the point a developer can safely assume you have JavaScript, and can force you to use it.
The article is written around supporting "users who have JavaScript off", which is an option on all popular browsers. I.e. it's about better supporting users who don't want to use JavaScript, not about supporting e.g. Internet Explorer 1.0 (though that could be helped by this kind of strategy too).
Which in practice is an irrelevantly low number of people.
Nowadays, unless you are serving developing markets, supporting legacy technology, or your website is truly just some basic static pages, it’s a buzzword programmers use to flex on each other. That’s about it.
I personally find it annoying because I grew up as a junior right at the inflection point, when all the tutorials were still saying it was the right thing to do. That’s a lot of work to do for something nobody - and I mean literally nobody - in the real world cares about anymore. I would sooner brag about how my blog still works on Safari bundled with Snow Leopard.
Or it's something fun for a hacker to blog about polishing progressive enhancement on. You're free to choose your own takeaway of course. Part of the experience of being a junior is learning when which type of approach makes sense rather than expecting anything one reads to directly apply to how their next project should best be done, regardless if it's popular or unpopular. Not everything needs to be practical for most people to be worth writing about!
This. The vast majority of browser exploits are in code related to the JS engine and its accompanying huge API surfaces, and even those rare ones which don't require it are often obfuscated/hidden using JS.
Exploits aside, the amount of user-hostile irritating annoyances that just disappear without JS is also worth mentioning. Many years ago, I remember a site that was completely usable, yet continually begged me to "enable JavaScript for a better experience!", so I tried it and was immediately inundated with popups, moving flashing crap all over the page, and other things that I did NOT consider a "better experience". Never again.