[rossipedia]

I think it's spread out here in this instance. The realities of the web are that a non-trivial amount of people are going to be using older, outdated devices. That's just a hard fact.

The web dev's responsibility here (or possibly his manager's) is on deciding what level of support they're going to give for those outdated devices.

Do Apple/Google/etc also bear some responsibility here? Absolutely. They can (and should imo) support older devices, much more than they do. But they're gonna chase profit, and at some point the costs of that support outweigh the benefit. That's just another hard fact of life on the web, one that developers should take into account when deciding what kind of support they want to give to outdated browsers with their code.

Luckily, for most things down-compiling to something like ES5 isn't incredibly difficult and can be automated.