I'd argue CSS took hold early: it was in an era where you needed a lot of hard-to-maintain hacks to get it to work in all browsers. Today as in the past, many people get CSS layouts just usable in IE 6, while they look as intended in standards-compliant browsers. If you want a site to look pixel-perfect in all browsers, it's still not pragmatic to use CSS rather than tables (or Flash). What's changed are the constraints: more people started using browsers that weren't IE 6, all the other browsers became more consistent with each other (or use the same rendering engine, Webkit), and clients have become more OK with websites looking different in different browsers as they've become more used to the way the web actually works.

But this will eventually boil down to a difference in opinion, and I agree with your point that it would be better for everyone if more people were quick to adopt technologies that are better in the long-run.