It never mattered. It only mattered that your site worked in the big browsers. Internet Explorer then, Chrome and iOS Safari now.

Developers would write their standards-compliant code, boast about it on Slashdot, then put in the hacks and weirdnesses to make it work on IE6. They could have skipped the standards step.

I don't say this is a good thing: I probably have XHTML pages on one of my old, private sites, and I ran them through validators.

But it was a waste of time, just like, I dunno, using WinUI instead of Electron is now, or not using React. Go with reality.