As long as you ensure compatibility then software doesn't have to be obsolete or incompatible. The Windows API is so stable that it's the most stable API available for Linux.
I can already run VMs and that seems like a more total solution. To have an integrated solution you would need cooperation that you can't get from obsolete systems. I can run Windows XP in a VM. But if I want to run a virtualized Windows XP application seamlessly integrated into my desktop then I'm going need a Windows XP that is built to do that.
- Fundamental prerequisites cannot be changed or abandoned, even where they impose limitations on the overall platform.
- System complexity increases, as multiple fixed points must be maintained, regressions checked, and where those points introduce security issues, inevitable weaknesses entailed.
- Running software which presumed non-networked hosts, or a far friendlier network, tend to play poorly in today's word. Well over a decade ago, a co-worker who'd spun up a Windows VM to run Windows Explorer for some corporate intranet site or another noted that the VM was corrupted within the five minutes or so it was live within the corporate LAN. At least it was a VM (and from a static disk image). Jails and VMs isolate such components and tune exposure amongst them.
What you and I can, will, and do actually do, which is to spin up VMs as we need them for specific tasks, is viable for a minuscule set of people, most of whom lack fundamental literacy let alone advanced technical computer competency.
The reason for making such capabilities automated within the host OS is so that those people can have access to the software, systems, and/or data they need, without needing to think about, or even be aware of how or that it's being implemented.
I've commented and posted about the competency of the average person as regards computers and literacy. It's much lower than you're likely to have realised:
And no, I'm not deriding those who don't know. I've come to accept them as part of the technological landscape. A part I really wish weren't so inept, but wishing won't change it. At the same time, the MVU imposes costs on the small, though highly capable, set of much more adept technologists.
I can already run VMs and that seems like a more total solution. To have an integrated solution you would need cooperation that you can't get from obsolete systems. I can run Windows XP in a VM. But if I want to run a virtualized Windows XP application seamlessly integrated into my desktop then I'm going need a Windows XP that is built to do that.