Whilst I was speaking about personal solutions, it scales to heritage as well.
You only need one VM for all your data, because the access method would be to present some storage with the files you want to the VM.
(Granted, there may be a point where the lack of USB or CD support on hardware may mean that you have to present it with a disk image, but it's still fairly trivial.)
I don't think updating all my documents each year would be practical. The idea that it would be practical for a heritage model seems ridiculous.
The VM is probably the best method we will have to ensure fidelity. It's the least amount of work for the best return.