A 4 minute porn video is not like a 40 hour video game. If you can't see the difference then I'm honestly sorry.
If you're shrinking the scope to this one specific creator for some reason, okay. The lowest tier is 5 bucks a month, if it's one video per month it's 5 bucks a video. So there's no big difference.
But thinking of the countless other creators that put out multiple videos per month, multiple drawings per month, multiple updates per month, it's better to pay one sum and get access to everything they do. Paying for each individually would cost much more money.
So the simple answer to your question is no, it wouldn't be better to sell separate movies. Not better for the customer, because it opens up the possibility of price gouging and getting less content for more money. And not better for the creator, because some people WANT to pay more than the minimum, they wanna give the creator extra money and be gold tier patrons or whatever. And that's how creators make better profits.