firstly, in the comic, none of the streaming service has the movie, so a site telling him this doesn't change that point.

second, 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

thirdly, often it's not a matter of whether or not someone wants to pay, but how much someone is willing to pay. This depends on many factors, which boil down to how much they want to watch the movie and how much they can afford. imo there are two acceptable ways to charge for entertainment: paying once for that particular piece and you get to enjoy it as often/long as you want forever, or you pay a monthly fee and get access to everything for as long as you pay. unfortunately, thanks to the fragmentation of streaming services, option b has become quite expensive and not a lot of people are not willing to spend that much, but they would be willing for a lower price.