In my view what we've learned is the standardization process doesn't work. We had IE and Netscape doing what they liked and we got innovation; we got javascript, we got iframes, we got embedded video. Sure, each of these is a mess, to a lesser or greater extent. But they let us build the sites we want.
Then in ten years of W3C we got nothing - just the blind alleys of xhtml and css 2.1. The web has only started moving again after the WhatWG basically said to the W3C "we're going to implement this stuff, you can either call it html5 or become irrelevant".
We have learned from our mistakes. We're returning to the netscape vs IE6 days because they were better for innovation than the ten years of emptiness that followed.
The ten years of emptiness were caused by the browser wars and its ultimate, unequivocal victor when it, and the technology it supported, became entrenched for an extended period of time. It's not as though the IE team wasn't innovating because W3C stopped them.
During the emptiness, technologies like alpha-transparent PNGs started out but never got anywhere because the gorilla didn't support it and what were you going to do? We got this idea to create layouts without using tables, but oops, box model bugs, I sure was glad to be working around the legacy of the days of innovation, and hey, wouldn't position:fixed be great? You had upstart browsers that couldn't access many websites because in the happy days of innovation the web decided that if (document.all) elseif (document.layers) was a decent way of writing code and it's not like anyone was going to rewrite those. Remember that innovative native client technology a whole bunch of banks and DRM sites decided could be good for secure, controlled internet experience? I think they called it ActiveX, sure did wonders for usability and practicality of actually innovating browsers that could not support it.
You say we've learned from our mistakes but to me the use of -webkit- and continued use of user agent sniffing (buggy, natch) suggests otherwise. Who'll be updating those sites two years from now, when Firefox Mobile's or X Mobile's rendering engine is the innovative stuff all developers love?
