Some developers are seriously considering de-listing their games from online shops when the Unity Runtime Fee kicks off at the start of next year, meaning some titles built on Unity could end up being temporarily — or permanently — unavailable. Here's what developers are saying about the Unity Runti...
Apparently they snuck a clause into an update to the ToS at some point, after years of saying they'd never do such a thing. So people agreed to a loophole without realizing. The legality of such a thing is highly questionable, hence the rumblings of potential lawsuits are already brewing.
If you want to change the terms of contract then you have to contact every affected individual or company and make it explicitly clear what terms of contract are being changed and then get explicit approval that these changes can go ahead. Obviously you do otherwise we live in a world of anarchy and business couldn't possibly happen.
When companies want to renegotiate tiny intricate details of contracts it often takes months because of these requirements, even when both parties are already in verbal agreement.
They can't just announce they are changing the contract and then provide less than 2 months worth of warning and say you don't get a choice this is the new contract now and forever and also in the past. They have to get explicit approval of this change, and obviously no one's going to give them it.