Sorry, I am going to call shenanigans on this statement. There was only one place I ever visited where there were closed 440 repeaters and that was in the People's Republic of California.
A good chunk of the western U.S. operates this way. I can't speak of how it's done in your part of the world. I don't go there.
I think you will find, in most areas, 440 repeater owners don't dare close their repeater since the users are already at the minimum. Why would they block more potential users on an already under-utilized repeater?
For a variety of reasons. Many closed systems are that way because of agreements with the site owner - say, employees of a site owner who allows use of the site by employees only. Some systems are built to serve a specific group of people, say, employees of a particular sponsoring company. The Edison 220 system comes to mind.
Some systems are rather complex, and require that users all be trained control operators. Some systems are oriented around a specific common interest held by it's members. Most of these closed systems are built and operated with specific goals in mind, and general public use can sometimes go against the specific goals. Some systems are hugely expensive to operate, and the only way to continue is to require a supportive membership. I could go on and on and on why some systems end up being closed or private.
There is this general idea that when a new ham gets their license, 2m (VHF) is the ONLY band available or even in existence. That could not be further from the truth.
I agree with you here, and believe that this is the fault of the people who are bringing these new hams into the fold. Out here, I see lots of CERT organizations sposoring classes and VE test sessions, and making available via group purchases 2 meter handheld radios.
I have always been a primary 440 user and had a bit of an evangelical attitude with it. I would love to see more people take advantage of 440. I think a lot of new hams buy a dual band VHF/UHF HT for their first radio and they never bother to explore the 440 side. It's a shame.
What's a shame is that many new hams are not introduced into the wider variety of activities ham radio has to offer, and are directed into repeater operation, whether it's 2m or 440 or whatever. It's the variety that makes the hobby so interesting.