Yeah, I guess you're right that the necessary prerequisite for alternative OSs like ChromeOS to be viable for consumers was the Web eating software for most tasks. I think most people doing business or personal computing on a laptop today are doing 100% of those tasks either in a browser, in a first-party app the OS vendor made, or in a simple Electron app that just wraps the webapp (Like Slack and Spotify). Obviously not true 25 years ago. It started coming true right before Chromebooks started coming out.
Arguably it's also the only reason Macs became viable for consumers instead of dying off. Imagine if you couldn't use any webapps on a Mac, nor "apps" that were built with Electron.
I've used a Mac from 2003 onwards, and it was rough in some ways before large web apps became common. Microsoft was seemingly throwing Apple a bone by making Office for Mac, otherwise I think the Mac would've been non-viable. And also Age of Empires II, which later on became Windows-only.
Arguably it's also the only reason Macs became viable for consumers instead of dying off. Imagine if you couldn't use any webapps on a Mac, nor "apps" that were built with Electron.