firstly, in the comic, none of the streaming service has the movie

This is based on what?

even if one streaming service has that movie, it might not be the one you are subscribed to. so instead of "just watch"ing, you have to make a new subscription on that service and pay for all their content although you just want one movie

Which is a different issue entirely than it not being available at all.

it's not a matter of whether or not someone wants to pay, but how much someone is willing to pay

Same thing.

unfortunately, thanks to the fragmentation of streaming services, option b has become quite expensive

The services have not become fragmented. There was never one streaming service that had all content available. They've just added more options.