You messed in the head boy. The developers don't care what you do in a single player game once you've bought it, ESPECIALLY Bethesda who pride themselves on making games that lets the players do w/e the hell they want. Todd Howard won't be sobbing in the fetal position if someone mods the game so that they are an uber lich with mad skills. Hell, my first 3 playthroughs of Morrowind on xbox I used the constantly recharging life glitch, well, constantly. Bethesda didn't call my house and tell me I was being mean and to play nice cuz it's not fair
On the topic of cheating in a single player game, just because its single player doesn't mean its not cheating. Cheating is cheating. You are right, that once you payed your money the incentive for the dev team to care goes down. But that doesn't mean they no longer care if you like the game or not after you buy it. They do give a damn, contrary to popular belief. They want everyone to have a good time and to enjoy the game they made. They didn't need to come up with the mountain of lore that they did, but they did. And its really confusing too, there's a real mystery to it. They didn't need to do all that side stuff, but they did for some reason. I happen to think that reason is that they want everyone to feel like this world they are making is a real one, with a past, a present, and a future.
Maybe its out of my respect of creative writers that I feel that not reading these things is an insult to them. The lore is amazingly complex, and to not read what they created is a waste. I'm sure they know full well that many people couldn't care less, but to me that is an insult to them. That's just my opinion, and you can very well think I'm crazy for it. Whopdy do, its not the first time I've been called crazy or an idiot on a forum before.
But how does all that I just said tie back to why cheating is unfair to the developers? Simple. They just spent five years working on something, and you undue everything in the time it takes to mod around it or cheat. The reason they allow people to mod is because they are fine with it, and they enjoy seeing the things the community can come up with. I however dislike that, but I by no means think that you shouldn't be able to do it. I just happen to dislike it and find it unfair. Disagree with me and call me stupid, I honestly really don't care. Its just what one person thinks.
Balance is important for every game, single player or not. I really can't think of a game that didn't have balance, because that would be one messed up game. Becoming a demi-god with magic or becoming a litch should be possible, but it should be near imposible because its so hard, and it should have drawbacks.