Not talking about re-writing. But there is an enormous amount of code out there in c, c++ and other langs that people would love to use in web apps.

In our case we use the same library code on iOS, Android, Windows and in the browser to do computationally expensive operations.

Also, to dismiss productivity apps such as PS and CAD as unimportant is kind of crazy. Huge business model change? They are still an enormous part of the software industry and the browser a great platform for distribution for many cases. Performance and code secrecy being two barriers that WASM solves for them.

Rewrites have never been where its at, there are so many new possiblilities web assembly opens.

Imagine if every AAA game had a web demo?

Imagine real support for Peer to Peer video that worked in several browsers and platforms?

What could editors in browsers be? Not just text, but any kind of office suite that exists on the local

Anything requiring a 3d canvas that was limited by javascript's speed.

The question of interest is "In a world where webassembly exists and is well-supported, would Slack have been written in JavaScript (or a JS-targeting language like TypeScript), or was there some other language the developers knew better that they could have worked faster in but the JavaScript tax prevented that option?"

> which would be a huge business model change,

Is it? Since Adobe switched to the subscription model and the "Adobe Creative Cloud" I'd say they would be quite happy if that infrastructure would be good enough to run their very big application suite(s). Not to mention the savings of not having to support two major platforms (and several OS versions for each) - even realizing them only partially would be big. Of course, given the size of their product I'd say there is little use in talking about this at this point, the web platform would have to mature a lot more first.