The thing is, I'm using WinUAEs 4.0.1, 4.2.0 and 4.9.0 (the latter for just one demo that doesn't work on the other two, and for potential future ones).
I've got Windows 10, and I haven't yet come across a Windows update that has broken WinUAE functionality, so I figure if the old versions work fine, then why change the demos to work on the new one? Very old Win32 programs still work fine on Windows 10, and they wouldn't deliberately break them for a new Windows version, for compatibility's sake. And some people, especially the US military, still use WinXP, long after it was discontinued and lost support.
A potential problem could be Windows 11, but I've decided I'm not going to upgrade for many years yet, if at all. I actually wish I'd never upgraded from Win7.
Anyway, if particular old WinUAE versions work on my current Windows, why upgrade? 4.0.1, the oldest, is only a few years old anyway, and while on EAB I saw many queries to Toni from people using ancient versions of WinUAE from the Noughties!
I don't think upgrading WinUAE is strictly a necessity at the moment. Besides, it'll give Toni time to iron out the sheer number of bugs in his rewrite, because, as I said, JIT looks broken at the moment.