What holeraw said.
Menigal: It is not necessarily a question of whether or not the developers care but rather whether a certain "improvement" is feasible (or perhaps even possible) or not.
1) Non-moving NPCs. Sure it is a nice feature, but you can pretty much double the development time if you want to implement this. Look at the number of NPCs in Gothic compared to the Elder Scroll games.
2) Repetitive Quests. Good point ... and then again not easily done. I agree that the "go kill x of y and bring me their tongues as proof" when put like that is boring, but the actual process of having to seek out a baddie or a group of baddies, do something (often dispose of them) and report back to the quest-giver is one heck of hard thing to remove from any quest driven game. Variations like the missing painter quest in Oblivion is a nice detour from the standard fare but let's not forget that this quest required a whole new graphical area to be made that could only be used in this single quest.
3) One Gameplay. Good luck creating an engine that is equally suitable for RTS, RPG and FPS gameplay and good luck to the design team that needs to implement 3 equally exciting gameplay portions in the same game without one of them feeling stale or rushed. Nice idea, not very realistic though.
4) Tutorials. Opinion, but while I tend to like tutorials, I wholeheartedly agree that they could often be made skippable.
5) Same UI. Again development costs. Most multiplatform games nowadays are developed on one platform and then ported to the others where necessary. However, with Microsoft's Games For Windows initiative where gamepad support is required, there really isn't that much incentive to use a lot of resources/time on developing diverse UIs.
6) Loot. He is Loot-gamer. Opinion.
7) Re-searching. Good idea. Completely dependent on the engine though. In the original Deus Ex, when the level design permitted it, you could turn around just before exiting a level and spot the stunned guard you hid behind a crate at the very beginning of the level ... however, savegames were HUGE at that time because every interaction you had made since starting the level was saved. Not as easily done in this day and age where one of the primary limitations of consoles is memory.
8) Spawning enemies. I agree, but necessary if you want to reuse areas for further quests. Therefore choosing not to use respawning requires a larger gaming world than would otherwise be needed. Resources that could otherwise have been used for moving NPCs perhaps?
9) Non skippable cutscenes. Absolutely agree. There is no reason that I can think of why a cutscene shouldn't be skippable. At least the second+ time you watch it.
10) Savepoints. Again, engine based. It is MUCH easier to implement a savepoint system than allowing to save whenever you like. The save files are usually a lot smaller as well. This is once again primarily an issue for consoles but like or not, the console market/audience is a lot greater than the PC market. (for most genres).
Just like it helps you become a better driver to actually ride a bike in traffic once in a while or walk the streets as a pedestrian, it also helps when gamers have a bit more realistic view on what can or can't be done within the time/money-frame a development house works with. When you're Blizzard you can do what you like, but most others have deadlines and milestones to meet and even the best idea can become too difficult or time consuming to implement and thus have to be cut from the game.