Under what circumstances would webapps not exist in some form or another? It's a system for deploying applications via the web, and JavaScript is primarily the language that they're implemented in.

I will bet you that in 99% of alternative timelines, we'd end up with something incredibly similar to what we've got today, and you'd still be complaining that applications aren't "native" enough, because practically nobody cares that a taskbar or button isn't a native OS component. They care that their application works, and can be quickly deployed and updated.