I honestly don't think this is too surprising. When a new thing is created that piques peoples interest they may create an account to try it out. A percentage of them will use it daily, some weekly and some will loose interest when it does not meet their expectations. De-provisioning or canceling accounts takes effort and walking away takes zero effort.

I expect a similar pattern with all the AI type services that are popping up. People will create accounts to try it out and the active accounts will plateau. Some percentage of accounts will stagnate as very few systems remove inactive accounts in the hope the person returns and becomes a contributing patron.