They were first to offer a frontier model which also meets enterprise requirements (i.e. not training on or retaining on customer data, able to purchase tokens through AWS and GCP instead of having to onboard a new vendor). They did so with a proprietary harness, which creates friction for teams inside enterprises to move (can't just install another harness - your IT org has to approve and configure another harness for you). In particular, they were the first to make their model acceptable for defense contractors, and defense spending is a huge market. (An F-35 costs $30k-40k per hour to run, you think an aerospace company notices $10k of API usage per month?)