>> Because these technologies came into existence after these browsers were made. Such is progress.
An example: the "about page" for Google Music. You need to download the newest Chrome to view it. I don't call it progress if accessibility and backwards compatibility get the shaft.
>>This is a law, and being blind is rarely a choice.
Two things: I hope you make sites accessible for the blind, not because it is law, but simply because you want the blind to access your content. Put another way: If it wasn't for the law, we could forget about the blind too? Accessibility needs a law for front-end engineers to take note?
Being on IE6 is rarely a choice too, especially in a corporate environment.
>>Because they were built with two codebases, one for regular browsers, one for IE6. Double the work for that 1%.
You don't need exceptions to make sites render on IE6. You only need exceptions if you start implementation in a modern browser, and make IE6 a minute after-thought.
>> But IE6 required a lot of browser-specific code.
Only if _you_ required hacks to make a design work.
>>Is that progress? Yes.
I don't think that was the progress that Tim Berners Lee had in mind. A progress where HTML documents from the HTML5 era become inaccessible to later generations.
Disclaimer: I am able to build sites that render in IE6, without much hacks or troubles or extra work, but I don't like working around its quirks. I don't have a strong opinion on why and when IE6 should die, and I certainly don't want to play that judge with my clients websites. I want maximum accessibility, and that includes IE6 in my opinion.