With repsect, I'm not sure that my story would be all that helpful. Suffice it to say that, like the OP, I feel "lucky enough" to have a TT position, and I know (as does the OP) just how difficult and fortuitous it is to be in such a position. I therefore understand the OP's quite understandable feeling of "stupidity," perhaps of guilt and unease, for wanting to leave while also knowing that he or she has it "so good."
By my reading, which I concede may be incorrect, dr_zack clearly wants to leave the TT, and is asking something like permission to do so. I heartily grant it, both for dr_zack and for the potential benefit of others. (OP: please do correct me if I'm wrong here.) The original post pointed stated, in part:
There has been some success there, but I feel it's rather limited in potential, and I have pretty much moved forward doing my own thing.
However, it's all made me rethink my place in academia -- not to mention that for he last year or so I just feel as if I am not really doing what I "should" be doing with my life and have untapped potential and interests. I also cannot see myself staying at this school or in this town forever. But, I feel I could likely get tenure if I "played" it right.
Then, in response to what seems a reasonable suggestion from txgalprof, the OP wrote that:
while I love teaching and writing (what I want and not under pressure), I could care less about the other aspects of being a professor. Part of me knows I want to leave, and yet part of me feels stupid because I really have it very good. :)
Finally (as of this posting), dr_zack acknowledged, in response to what I agree are very helpful remarks from glowdart:
I guess in my head I thought that if I resigned now I would feel more free to put time into finding new opportunities, but I'm not sure how much logic or reality is really in that thinking.
All is to say, again, I think that dr_zack wants to leave the TT, and that some of the "encouragement" (though certainly well intentioned, reasonable, and useful) is in fact discouraging him or her from pursuing desirable alternatives. Yes, I also think that an unhappy professor in a tenured or TT position is (blamelessly, perhaps) preventing someone else from occupying such a position, someone who might desperately want to be on the TT, indeed, someone who could truly say that this job is "what I 'should' be doing with my life." But I still believe that if dr_zack wishes to leave ("I know I want to leave") to pursue "untapped potential and interests," then I will applaud the admittedly tough but ultimately correct decision to do so.
dr_zack, please weigh in if I'm out of place here, and if I have misinterpreted or misread your remarks. I will certainly apologize. Either way, I do wish you all the best, whatever your decision.