I don't know, if you have an Alpha and you simply write a fast hardware virtualization layer I don't see why you couldn't sell those machines to the exact same costumers you did before.

Now Alpha was a bit late but the same strategy could have been adopted earlier.

IBM has the same costumers and has virtual layer onto of virtual layer to support technology from the 60s.

You then also port the OS to some RISC system and x86 and attempt to get new costumers using VMS on those system architectures.