Their API is unusable due to rate limits. Myself and my wife have both had ideas, started using it, and found other approaches after hitting rate limits. I tried funding more money in the account to increase the rate limits and it did not work. I imagine they see poor growth there because of this.
It's pretty trivial to get increased limits, I've used the API for a few consulting projects and got to tier 4 in a month. At that point you can burn near $200 a day and 2 million tokens per minute.
You only need 45 days to get tier 5 and if you have that many customers after 45 days you should just apply to YC lol.
Maybe you checked over a year ago, which was the wild wild West at the time, they didn't even have the tier limits.
You need to use it for some time to get into their higher tiers of usage. I used to also have this problem and it annoyed me greatly, but once I got to usage tier 4 it never happened again (except for o1-preview but that just wastes tokens IMO).