Equal or greater value is in the mind of the passenger. If I've chosen my seat a few weeks ago, and decided that I wanted exactly this seat, and I'm already sitting down and put my suitcase up there, and my bag down there, and my stuff in the pocket... Then this is the best possible seat for me. To be worth moving, it would have to be in first class.
You don't realize how much more thought into planning you put in than the average person. I mean, go read your colonoscopy prep post, it's a thing of beauty, but not at all relatable to most people. The average passenger doesn't care where they sit in the slightest. The concept of looking at seat guru is entirely foreign to most people.
It's simply not an inconvenience. If someone is situated, and moving means more than just grabbing a novel and purse, then I have seen people refuse, and it is totally understandable. That's why if you aren't able to book seats together and you plan on asking someone to switch, it is important to board as early as possible to ask people before they get settled.