It's my presumption that these services are expensive now but once proven will become commodity. In sufficient time it would be as cheap/free as penicillin or a multivitamin.
If you had a large country like china or the us or some other big baller walk in and say, "make 5,000 MRIs to these specs and we'll buy them" then by the end that manufacturer could quite possibly crank out another 5,000 for comparative pennies and flood the market, but until someone puts a few billion on the line it's not going to happen.
Are you sure about that?
Commercial: https://hyperfine.io
'DIY':
https://hackaday.com/2015/05/04/hackaday-prize-entry-a-low-c...
https://www.eevblog.com/forum/projects/building-an-mri-machi...
https://www.ismrm.org/22/program-files/ET-08.htm
https://www.researchgate.net/publication/385920900_ezyMRI_Ho...
^^^^ Those actually aren't the ones I remembered, there was something in between that 'DIY' stuff, and the commercial thing a few years ago. ISTR also commercial, but slightly less bulky. But can't be bothered to search for that now. (Probably something related to https://duckduckgo.com/?q=rebco+mri )
There is also commercial mobile stuff for veterinary use.