This quote is adorable considering the size of most pages today:
"This approach has several disadvantages, the first of which is speed. You are gratuitously transporting potentially many kilobytes of data back and forth across the network."
I was there, kB were an issue. We had 56 kb/s modems vs (let's say) 56 Mb/s fiber now. We gained a x1000 factor and we're dealing with many MB now instead of many kB back then. Page size grew x1000 too.
But loading pages was really slow, mainly because browsers were slow. No parallel loading of images, no progressive rendering. Those were the first optimizations.
I think you underestimate the effects of high bandwidth. There was a sweet spot in the late 90's when some people had broadband (early cable modems, generally 3 megabits, or DSL.) I had an ISDN line from 1996 through 1998, then a cable modem after that. The web was fast because it was built for dial up. As broadband gained more and more market-share, the bloat increased.
"This approach has several disadvantages, the first of which is speed. You are gratuitously transporting potentially many kilobytes of data back and forth across the network."