I'll preface this with noting it's a little odd to act as though adding 80 MB of unnecessary JS is a popular idea on HN.
They couldn't if they needed to work asynchronously. Or if they couldn't speak or hear well over the phone, the likelihood of which approaches 1 if you have so much as a different accent. Or if you don't want the other person to hear your accent.
It's a bit cliche maybe, but I know people who've benefited from all of those features of IP-based communication, and they're reasons to be happy about the Internet. And since just about any telecommunications system that transmits voice can be bullied into transmitting IP packets, there's really little cost.
I mean, we can all agree, I imagine, that many pages have too much JS. But then what do we cut? My idea of what's "useless" is probably different than the people cutting my checks. Saying pages don't need "unnecessary" JS is tautological but not really illuminating. I do think there is plenty of reason lots of people would benefit in their work from single-page applications, not to mention video and audio that would dwarf the JS anyways.
My point is that the kinds of CRUD and spreadsheet manipulation tasks that most people who don't work at a screen all day need to do on a screen can be done over a trivially tiny pipe if that pipe is used with at least a token amount of efficiency.
