How many is "many"? Looks like the only affected apps were those which provided a different means to access Twitter without ads. This feels like a storm in a teacup with the majority of developers on the API being unaffected.
I'd be happy to pay some sort of subscription to the API in order to keep using the third party client. Not sure why this isn't a thing. I'd much rather pay a fe bucks per month for API access than "Twitter Blue" or whatever.
As for the apps: while it's an asshat move, I'd be really careful about building anything commercial on top of anyone else's project without any guarantees about the service even existing tomorrow.
https://docs.google.com/spreadsheets/u/1/d/1O27Co27g2fWRon7g...
Isn't that the whole purpose of an API to send and retrieve content without ads - or any other presentation-layer addition?