Yea, the browser based web keeps losing market share. First to mobile apps, now to dedicated document readers. Both performance problems. But the slow document problem is not very technical, mostly politics. There's no mechanism for enforcing requirements across a wild west of bloat.

Flash's demise was for similar reasons. Bloat caused by over eager developers gained it a reputation for slow loading times and unusable websites. In this case the usable web is punished too.