The stupid part about that logic re:images is that you get graceful degradation for free in systems that don't implement the additional Accept header.
Re:WebKit has implemented srcset
by lukeschlather on Wednesday August 21, 2013 @09:09PM
(#6254446)
It's not stupid. From an academic perspective, sure it works either way. From a business perspective, you have to support the full feature set on a given set of browsers, and you're not going to waste time on a solution that only covers 80% of your required browsers when you can write one codebase that covers all of your browsers.
That would be way saner, the problem is that it seems no one wants wants to touch HTTP. Browser vendors work under the assumption that whatever feature they implement, it only has a chance of being adopted if it can be hacked in other browsers with javascript shims.