What happens in meatspace if you pay a cover charge to enter a place, and then don't follow the rules of the establishment? The same thing, you will be asked to leave, and trespassed if you refuse.
Just because you paid to access someone else's servers doesn't mean that you can do anything you want, with no way for the owner of the server to enforce any rules. It works like this with any kind of service on the internet. Games are not any different.
If I pay a lifetime membership fee for a meat space, and they ban me, I expect the lifetime membership fee to be refunded, subject to reasonable prorating, even if they claim I violated their "subscriber agreement".
Anything else would seem to me to incentivize banning as many lifetime members as possible before significant consumer retaliation (e.g. maybe we'll just ban the lifetime members with low social clout), to reduce costs and maximize profits.
It's not purported to be perpetual, the EULA is defined as the "subscriber agreement" and it's clearly laid out that violation of anti-cheat protections violates the terms of your game subscription.
Just because you paid to access someone else's servers doesn't mean that you can do anything you want, with no way for the owner of the server to enforce any rules. It works like this with any kind of service on the internet. Games are not any different.