Not sustainable as opposed to what, exactly? Developing and maintaining a completely different mobile operating system? Focusing on truly open platforms sound nice in theory, but completely falls apart the moment you consider what people want to do with their phones compared to the developing resources available.
> Every single chrome-fork has shut down MV2 extensions, even Brave is about to do it
That's just wrong, there are other forks that still support MV2 extensions right now, and at least brave has no plans of shutting down MV2 extensions even after Google removes MV2 from upstream completely. It will certainly add maintance effort on brave's side, but they already patch a million other things that upstream doesn't support.
Brave said they'll try to maintain temporarily limited MV2 support for only 4 specific extensions, but recommend Brave Shields as the go-to adblocker for the future. Google is about to remove most of the MV2 code from the codebase, which will explode the complexity soon.
The cost of writing code has fallen 100x in the past 3 years, and will likely fall 100x further. So actually, yes, thanks to AI it probably actually is reasonable to launch a fully new stack from scratch.
Maybe, but the cost of actually shipping a product has fallen by maybe 10%. I don't see dozens of production ready mainstream OSes and web browsers popping up because LLM can dump tens of lines of code per second.
Give it 12 months, you will see dozens of from-scratch large scale software projects shipping. New web browsers, new operating systems, new gaming engines, new productivity software, we are at the threshold of having an abundance of software that was previously only available from large corporations.
Multiple open source desktop/laptop operating systems are maintained.