I don't know if it will ever come with a vanilla Windows Home edition install but somehow I doubt that.
I don't see what they have to lose. Windows is still used widely in business. But their lock-in has drastically reduced with the rise of iOS, Android, and web apps. Making Windows more attractive as a platform for developers to deploy applications, even if it is through the WSL subsystem will make Windows as a platform more competitive to these other ecosystems.
I am currently writing scientific software. But we have stopped building Windows versions, since these programs work great with WSL and it is far less effort than building these applications separately with Visual C++.
I'm currently in a weird spot with the software I distribute because the majority of the users "know enough to be dangerous" but aren't software engineers/IT professionals. We want them running code and using Linux like a pro, but there's a lot of training/documentation overhead just for our *nix builds and the friction to getting that up and running for WSL is daunting.
Luckily MS understands B2B native more than anyone else so I'm hopeful they'll have a solution eventually, but I'm not holding my breath until then.
I am not sure what the difference is, when WSL gets deeper and deeper integration with Windows. WSL2 does not use the personality mechanism anymore, but that's just to make it easier to fully support Linux. But once Linux becomes a personality of Windows in the informal sense, targeting Linux means targeting Windows at the same time.