oh don't get me wrong if I had a plan for it I'd be doing it. I've always found it really weird given the impact that Electron had in app development, why Firefox never tried to ride that train. I know of one short lived effort to take the engine out of the browser.
Usually the answer is limited resources with unclear payoff, i.e. even with Electron's success, it's not clear that there's room for an alternative in the market, and it'd be a lot of effort to do.
Tauri v2 just got released, it’s very recent and corps move slowly; besides, rewriting a project in a different framework is a major undertaking, it would be a bad idea to rewrite a major project in Tauri, which is still not as widespread. I’m unfortunate enough to have to work with Electron and Tauri greatly improves on everything that is wrong with Electron. I have no doubt that companies will begin adopt it in the following years (or a similar tool, the underlying architecture is solid).