Paying for software is one thing. Paying for software where the amount you pay may be all but completely dictated by the supplier is another. If you decided to pay for a relational database, you could, with some work, swap vendors. If you paid for datomic, you could not. That makes it a non-starter imo as a technology decision. The business model here is naive and will change or datomic will always be super-niche. Maybe that's be design, but it's a little sad to me as it sounds like the tech could do some real good.

edit: typo