Why is it hard? Ultimately you take whatever your signal is and send it to some relatively cheap LLM.
How is it easier to sign up and manage a different service, implement a different API, etc.
And from the company side the fatal flaw is that these types of tools rely upon 1% of their users having huge spend. Nobody is going to be a huge spender here because it's easier to hand roll than navigate procurement on this (not to mention impossible to justify the spend, additional security/privacy risk, etc.)
It feels approximately impossible for this company to have large accounts.