However, you can only close them from Control Tower at the rate of 2 to 3 per month, due to a hard limit quota which cannot be changed, even if you request it. Needless to say, this sucks when you've followed AWS's own best practices and created lots of accounts using Control Tower's "vending machine."
AWS's archaic account model is one reason we've switched to GCP.
https://docs.aws.amazon.com/organizations/latest/userguide/o...
Maybe it was quicker to implement with a hard limit, or there is some internal service that can't easily handle large volumes of account removals. But if it was Amazon losing money from this limitation instead of the customer I imagine it would be fixed pretty quickly.
Now has an API (with some caveats)