In defense of your players, they may just be "causal gamers", and I'm sorry but the minutae of D&D rules may not appeal to their idea of "fun". I think the suggestion above might be a good one, try a game with less "crunch". I personally love C&C as a game and would recommend it highly, but it's not the only option out there.
My group are casual players and I have realized it's not necessarily a bad thing, just something you have to compromise for. This is why I've kind of grown disenchanted with D&D myself, it really does require a substantial investment from players and doesn't work well when that investment is lacking. My players love the "adventuring" aspect, enjoy the story being told and like to roleplay. But they very rarely understand the intricacies (especially as pertain to combat and magic), terminology, etc of D&D. Find very little fun in keeping track of their options, modifiers, etc. But you know what it's cool with me because I was also starting to get a little bogged down DM'ing D&D.
Now I can also see it from your perspective, you seem to enjoy the "crunchier" aspects of the game, tactical choices, etc. Have devoted a significant amount of time to "rules mastery" and enjoy those aspects of D&D. I can't help but think you and your players either...
A.) Don't want the same things out of the game.
B.) Aren't willing to devote the same amount of time for the game
C.) Need to find some sort of compromise game(if in fact you wish to keep gaming with these particular people)
Me, I found a game that suited me and my players, but then again I had grown steadily disenchanted with the rules minutae of D&D and wanted a change that coincided with my players preferences.