The only instance I know of where LMB will not spawn successfully is with a lot of crowded lepomis (BG , GSF etc). They will spawn in very bad conditions even worse than BG and a lot worse than Crappie. Muddy water , floods , cold spells , you name it. If one spawn gets wiped out they will try again. If you think about all the places they inhabit they have to be very adaptable.