[fabrice_d]

They do, because web content can live for a very long time - that's a strength of the web. So today's and tomorrow's browsers need to be able to process these 25 years old documents, because they are still part of the web, syntax issues included and no one will come to fix them.

[reginaldo]

The counter-argument from the embassies point of view would be that, since you're running the browser on top of the simpler execution environment, you could ship the exact version of the browser that works with your content. That way, only the execution environment (i.e. the simpler APIs) would have to be backwards compatible. So content could theoretically live longer, as we'd ship the interpreter of the content along with the content.

[iopq]

You can just load that content in another browser.

If your browser handles all of the popular sites, people will use it. Nobody cares about whether Flash loads anymore, do they? Yet there's millions of Flash animations and games never ported to another platform

[fabrice_d]

The web is made of links. It's quite annoying to switch browsers when following links.

[dane-pgp]

I think the idea would be that when you click on a link to a 25 year old page, the browser brings up a little warning saying "This page is 25 years old and has some errors that may stop it displaying correctly. Press the Refresh button to re-render it using an older browser engine."

In the worst case, the browser would then have to download some additional code that contained all the support for invalid HTML/CSS code. In the best case, the 25 year old page would be served with a header containing a cryptographic proof that the site really had been around for 25 years, and it wasn't just some newly created attack site that was exploiting some weird behaviour in old renderers.

[iopq]

Again, nobody linked to Flash content in a while. You might still encounter it in the wild and it won't work. I don't hear anyone complaining.