> And that for users with slow browsers, slow/spotty Internet, etc., an architecture that uses a heavy front-end framework produces a worse overall experience than what most e-commerce sites were able to do in 1999.

I think this is heavily dependent on company focus (and to some extent - the data requirements of the experience)

Basically - I think you can create a much stronger, more compelling experience on a site for a person with a bad/slow connection with judicious usage of service_workers and a solid front end framework.

But on the flip side... Making that experience isn't trivial, requires up front planning, and most companies won't do it.