Is there any value to keeping it non-free? Do they still sell it to commercial customers?
OTOH, freeing such a code base is costly, especially if multiple licenses cover different parts of the code or if the code contains references to stuff that you don't want to go public.
The real question is: what do they get out of offering a hobbyist license? I honestly don't think they get anything and it's just a nice gesture of goodwill. Nobody is going to pick up the hobbyist VMS license and then decide to adopt VMS at work. I bet it doesn't lead to a single extra commercial sale. It's nice that they're offering it despite that.
While I think you're probably right, having the hobbyist x86 option might help with testing and identifying bugs though, due to the larger user base.
Commoditize your complements: If you sell VMS software, it stands to reason you would like there to be people who know how to use it. Even better if you don’t have to pay the train them.
Tons of people know how to use Linux because you can just download a distro and start using it… It’s the same reason MS and Cisco have all those certificate programs.
I never understood why IBM didn’t make a hobbyist version of their mainframe OSes for Hercules.
VSI knows all of this, of course. I really don't think they intend to compete with Linux in 2023 with hobbyist licenses. That was never in the cards.
I think part of it is hoping to encourage open-source software ports over to OpenVMS.