[chimeracoder]

> That being said, they can't be expected to provide free or low-cost apis across the board forever.

They did, for most of Twitter's history

> ...otherwise everyone's gonna just constantly use them to the detriment of the entire platform!

On the contrary, the free availability of the Twitter API is inarguably what drove the growth of Twitter as a platform. Twitter benefited far more from it than the low marginal costs of operation. It's not even close.