Jeaton - FWIW, I have been in three MFL dynasties for almost 10 years each, entering my 5th year in one FFPC dynasty, and just picked up a second FFPC dynasty orphan late in the off-season (FFPC Rookie Draft date). I trimmed down a couple of MFL dynasties after a couple of years, due to not being comfortable with the commissioners and turnover in those leagues themselves - not because of my rosters therein. And the same is true for another mid-stakes dynasty team after being there two years as well - again for the turnover reason, which tended to result in very successful teams and very unsuccessful teams, and a couple of teams in the middle where I was at worst. My roster was gobbled-up in the blink of an eye, and maybe I'm successful enough to be playing with a minimum outflow of personal monies. And I do also play in a few redraft leagues, in which I cover my expenses plus.
As far as being a commissioner I'm going into my ninth year now, I've seen a lot of turnover in a 16-team full IDP dynasty with an 18 player starting lineup, in which I've never finished first but came close twice, and in order to have an attractive & competitive stable product for the real hobbyists that play this game - I've had to two-step the format down to 14 and then 12 franchises which will endure long after I'm gone from the face of this earth. So, I'm not really a "cut and run" tactician as you mentioned, but one who knows where to put his energies & time to participate and contribute to this great FFB hobby.
Thanks for posting your comments herein, and the best of luck in your continuing career as a dynasty baller.