"The comparison to OS/2 doesn't really work"
I think you are missing my point. OS/2 ran Windows 3.1 apps so well - in fact, better than real Windows 3.1 - that no one bothered to create native OS/2 apps. Which helped to kill OS/2. By the time Windows 95 and NT 4 came along, OS/2 was dead.
So if there is a need for "lightweight standalone apps", and these can be had via Android emulation, who is going to bother to write a native Windows app/widget/PWA? Developers love nothing more than having less platforms to support, which means fewer app versions to support. Which means less headaches all around.
Again, running your competitor's apps is not a viable, long-term solution. It's actually an admission that you are in decline and are desperate for new apps. As more devs see that "I can get Android users and Windows users with a single Android app", the situation only gets worse over time. It creates a downward spiral that Windows does not need to be in.