It's not a great idea. Perhaps best used on new members/new seasons, rather than stuff that's a couple years old. It's a way to stop the wait a year, subscribe and binge for a month that cuts the profits off a 12 episode series from 3 months to 1.
While a lot of people talk about taking one month, binging, and then turning it off, I am not so sure they are such a large number that it would justify putting a roadblock in the way of other users.
I suspect most folks just buy the subscription, or intend to do one month, but never turn it off. The providers would love these people - paying for the service, but not actually using it most of the time is like printing money. They would not want to disrupt the experience of the moneymakers.
Another idea in my back pocket is that vendors who make original content that we pay for, owe us a complete series. Unlike NBC, who is paid by advertisers, so if a show tanks, they cancel it. I paid Netflix to make The OA. They Owe Me.
Define "complete series" - The Good Place is ending after four seasons, because that's the story they set out to tell. Supernatural is ending after 15 seasons.
Do you want to pay up front for several seasons of a show whose quality is not yet known?