If I had a time traveling magic wand, the one Software Thing I would wish for would be that native, cross platform toolkits had won the war rather than the whole industry punting and declaring The Web Browser to be the target platform, or these super-high-level Game Engines. For decades, I always hopelessly thought the OS and hardware gaps would eventually be bridged by something like Qt or SDL or wxWidgets, and we'd…
Meanwhile, a ton of apps and games are completely agnostic to those cutting edge platform differences and are going to thrive in least common denominator sandboxes. And making those sandboxes easy to use for some specific style/genre/skill-level is always going to be the competitive difference between them. So the big high-level things are always going to exist too.
But… so are the near-metal abstractions that let you cut through and interleave cross-platform and platform-specific code even in high-performance paths.
You wanted the last group to “win”, but the ecosystem inevitably involves all three. There will always be something like Metal, there will always be something like Unity, and there will always be something like SDL. Winning isn’t necessary.