It's the same way in reverse. If a team signs a player to a stupid contact do you think they should be able to weasel out of it? Minnesota is gonna have to live with Kirk Cousins the same way Earl Thomas needed to live with the last year's of his deal.
If Earl Thomas didnt like this contract why the fuck did he sign it? I seriously want to see your answer that question.
I am sorry, but you are wrong. Regularly teams get the better of players by signing them to multi year contracts with little or no security for the player after the first year or two. It is almost exclusively in favor of the team over the player.
The Cousins deal is the exception, not the rule.
The thing is that Thomas holding out wasn't even about how much he was getting paid this year, it was about him getting an extension so he could be with the team long term, possibly for the rest of his career. They basically shat in his lunchbox and you know what, he showed up and went to work when the deadline came. He got hurt, was understandably pissed at the team for forcing him to show up without extending him, and now he gets to go to free agency where some other team will pay him.
I am not sure if he was asking for too much money, he could've been, but for someone that publicly stated they wanted to be a Seahawk for the rest of his career the team really did shit on the chances of retaining one of the best by not negotiating another extension for him and forcing him to play out the last year of his deal.
Most big deals do not make it to the end. I think you can agree that the typical stars in the NFL renegotiate before the end of a contract. This is fairly common so I am not sure why it is confusing to you.