Why would virtualization not fit the iPad model? It's all about isolating apps from each other and from the system, and ensuring that no mucking around can render the system inoperable. Virtualization is the perfect solution to enabling legacy or technical workflows on such a device without compromising the core OS.
Any app can be evicted from memory at any time, requiring a full restart. The VM could be terminated with zero notice, aborting the OS kernel and leaving the filesystem in an arbitrary state. There is no swap on iOS / iPadOS but even if there was you wouldn't want it burning out your soldered-on storage chip.
If the answer is that this VM program is the only one that never gets killed under memory pressure, bear in mind most iPads still have only 8G RAM so the OS will have to get even less than that, not leaving very much for any workflows on either the host or guest from that point on. Even that is still less capable than macOS on the same 8G RAM because at least macOS can use swap.
It's egregious that you can still buy laptops with 8G RAM today, but at least all of that is available to the OS all the time, it doesn't just abort under memory pressure, and it can swap.
Virtualization may make more sense with a different host or guest platform, but in this particular combination, memory will always be a problem. The lack of swap compounds that further. (I'm not sure about memory compression in iOS but you can't exactly rely on that for already-compressed data)
Even if the host and guest share memory to avoid the hard cutoff, there still needs to be a way for the iPad to free up memory on demand, given that it cannot use swap.
