Demand. When the first 5,000 units cost a mil a piece, few manufacturers are going to go all in, especially when a product improvement could make their systems obsolete before they're finished being built.

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.