EULAs aren't always legally binding. Often they contain clauses that are contrary to statutory rights, which can make the whole thing come down like a house of cards. Take the very thing you brought up: Devolution breaks the EULA. Well, in this country, I'm perfectly within my rights to backup a game to a hard drive. However, for that backup to be useful, there must be a way to play it legitimately. So, the EULA tells me I can't do that, but my statutory rights say I can.EULA's aren't above the law, but they ARE legally binding. That's why they are considered so shady. You are agreeing to a legally binding contract by using the software, giving the license holder rights to take legal action if you violate it.
Now, more than likely that would never happen, I just wanted to make a point
Of course, a company also has the right to deny service to anyone, as long as it's not in a discriminate manner. They technically don't even need an EULA to ban you from their online services.