But again, this requires starting from a point where "doubling the resolution" would work in the first place. On OS X it works. On Windows it wouldn't.
You're misinterpreting the problem, because your solution would only work for applications which never declared anything about how they should handle different screen sizes, resolutions, or DPI settings in the first place. In such cases it obviously would be fine, and what you're suggesting is what Windows has done for a decade now (simply scaling up the applications and making them look blurry until developers redesign things correctly).
Rather, the problem is with applications which claim to be DPI-aware, but in actuality are not DPI-aware. That's where Windows tries to treat them correctly with DPI awareness, but since the applications falsely declared what they support, they end up broken in high-DPI screens. And hence the workaround you suggested wouldn't work, because the workaround wouldn't be applied to applications which declare themselves to work correctly.
That's what the blog post I linked to is describing, including how they're working around it (among other things).