Sorry to pick on this point but depending on your application this should be more (or much more) important. Too many teams have this same opinion and it's glaringly obvious how little they care about performance. I'd agree that raw performance isn't really important, but the ways you can and the tools you have to optimize the performance of the app are if you find that you have bottlenecks is and this does partially depend on the framework.
That said, I would agree, all frameworks would probably be fast enough for most use cases, and even with the optimization aspect arguably the most important aspects are about application structure and how the framework forces you to structure your application. As you mention, I think this is why React wins, the way it forces you to think about things unidirectionally, think about state and components separately, etc. are all big wins for understanding your application.
Also worth noting is that Svelte doesn't really have a big company backing it like React does and so the ecosystem is smaller, which could contribute to its relatively small size.