I think its own popularity has been its downfall. Before, they were willing to waste money on servers and electricity to advertise ChatGPT, but the time has come to make it profitable and they have to tone it down to meet both increased demand by the users and the demands of their own sustainability.
They could make it paid only today, and it'd be instantly profitable. Most free users would transition to a free alternative, but the corporate world would easily pay for use. So would some power users. But I'm sure they are making good money with all the API use anyways, the free access is a cheap way to get mass testing and training data.