I think it's important to realize that what's important to our users are their own users, who aren't developers. My main drive for this project is to be able to easily make a product that works and feels great on all devices. If Gadi the business owner is getting negative feedback about his app from his non-technical users who are the main source of his income, he'll stop using a library that doesn't deliver. I don't want this to be a library that's only relevant for a minority of early-adopter end-users.
The problem with the w3schools stats is that it's from their own log files... i.e. it's showing the browser/version share used by web developers, which relates back to my point above.
I usually use http://gs.statcounter.com/#all-browser_version-ww-monthly-201509-201509-bar, although to be honest, I never really looked into it more than the fact that it's the source wikipedia uses. Anyway, according to that (for September until today, and rouding off):
- 22% Other!
- 20% Chrome 45
- 14% Chrome for Android
- 10% Safari iPhone + iPad
- 7% Firefox 40
- 6% Chrome 44
- 6% IE 11
- 6% Android
- 5% Opera
So yes, Chrome does a friggin' awesome job at keeping itself up to date. But it's not all inclusive. For the reasons I mentioned above, I think it's important to, at the least, support the last 3 browser versions (that increment quickly, e.g. 4.5 months back), and yeah, I at least am fine with IE11+. Just remember that e.g. for ES6 it's still not properly/fully implemented in the dev releases, so, even if 4.5 months from now, it won't be ready.
Also critical is to verify what happens with Cordova! This won't be in browser stats since it's "local browsing". We need to know what engine is used for Android/iPhone and how it's kept to date. I think for Android since 4.4.4 they use Chrome which is kept up to date, which again, is friggin' awesome. For < 4.4.4, if it's really important, we can just build with crosswalk which includes the chrome engine inside the app container (but makes for a +100mb app). For iOS I'm not sure how it works, anyone?