3. Not just because, but yes. Usually because of some "off" reason-certain holidays, bad weather, major events that keep people away from the theatre, a last minute cancelled theatre party, wed, matinees for shows that don't appeal to that crowd etc. The best chances for the best shows are very early previews which is why those in the know have an advantage.
Pinto, join Gold Club by the month first which is cheap, and see if you find what you are looking for. Or join will call which is cheap for a whole year. Or both. Or play by play, or audiences extra etc etc etc. Or do nothing.
Don't expect a lot of broadway shows on any papering site, and don't expect consistency. And expect that when a show is on one it is probably on the others. Although not always, but again there is no consistency. And try to expand your horizons and go see something off or off off broadway. that's where much of the best stuff is anyway. or go to the opera, or a concert, etc etc etc
If you read between the lines of the posts above, your intransigence is driving some people crazy.
Just sent Theatermania an e mail to cancel my membership when it expires in mid August. I hardly used it so it was crazy to renew. Maybe in a year or so I will try again. Maybe it will have improved & maybe not.