By this logic requiring web devs to write ES3 code should be acceptable too.
The platform changed significantly, improved significantly, in the past few years, some of these major advancements can't be ignored just because a browser doesn't implement them.
Nope, you can compile code back to whatever ECMAScript version you like with tools like Babel or TypeScript. So the devs don’t even notice that they’re compiling to 4-5 year old ES.
That's actually not true in general, tell me how to compile Proxy and regex lookarounds to ES5 or whatever version that doesn't support these features. In fact tell me how to polyfill these features in any way at all.
There's a proxy polyfill. And if you really wanted there's at least one pcre2 wasm build you could wrap to make a polyfill, lol. Barely anyone uses lookahead/lookbehind even in pcre, though.
Proxy polyfill: assuming you are referring to this [0], since I haven't seen anything else like this, then I'll paste here what the readme says:
> The polyfill supports just a limited number of proxy 'traps'. It also works by calling seal on the object passed to Proxy. This means that the properties you want to proxy must be known at creation time.
i.e. that's not a polyfill for Proxy. It's a polyfill for a subset of the thing, maybe that's useful for somebody, but it's useless for the use cases I had for Proxy so far.
Shipping an entire regex engine with your app: right, that's the only way to do something like that. Not that that's actually the same thing though, I can't just load this and use lookarounds as normal, i.e. it's not a polyfill.
For all practical purposes these features are not polyfillable. If your idea of a polyfill includes not actually polyfilling the entire thing or shipping an entire engine with your app then sure, anything is polyfillable, you could even run Java in the browser.
Electron does not weigh 300+ MB for starter, and one means basically statically linking your app so that it ships with its own dependencies and works more consistently, while the other means shipping a language because the one you have to use is not implemented properly by the platform, pretty different things when you look at them. I'll give you though that in both cases you are shipping a big engine with your app, so it kinda sounds like the same thing.
Having web developers learn C++ and Qt instead would be much more unacceptable.