[delta_p_delta_x]

> As someone who’s trying to kill desktop apps once and for all with the progressive web app revolution

Yikes, I hope not. Powerful, native desktop apps are what got me interested in computing, not the Web.

Browsers are a good use-case for kiosk-based computing, I don't disagree, and there are many use-cases for effectively booting directly into a browser (i.e. ChromeOS) but when it comes down to wanting pedal to the metal, I always reach for native technologies. It provides both a better developer and end-user experience.

For instance, you asked what a spreadsheet program might need the OS for. Many spreadsheets are used as databases (even if they shouldn't). A high-speed asynchronous I/O API is pretty critical for responsiveness, without going through the interpreter and GC of a browser.