Morgan Freeman gets a lot of roles because he's one of the best black actors out there. Filmmakers don't want to take a risk on casting someone who may end up giving a sub-par performance.
But you have to remember that actors have bills to pay too. The notoriously awful director Uwe Boll has somehow managed to put together some very impressive casts, only to fail miserably each and every film.
The cast wasn't interested in that film because it had potential to win awards (aside from the Razzies, which he has "won" many). They chose it because it was a quick paycheck and only took a couple weeks at most to make, which is probably the case for most of the actors in Lottery Ticket. It's probably a nice break for an actor to do some lower production films that they don't have to put too much heart and soul into.
But I have to agree that it's kind of disappointing to see such high profile actors doing such an awful movie.