Caine forgot being asked once on Carson about why he made so many less-than-stellar films. His simple reply "Its my job".
Memory does strange things once you get older.
I don't like all of Caine's movies and he's apparently been in some that must've been C or D flicks, but I don't remember ever seeing him give a bad performance.
Actually, this is Caine's great strength. He works all the time---and it's the actor who improves the scripts, so it's no wonder that so many of the films he's in, "Dirty Rotten Scoundrels," "Zulu," "Educating Rita," could have been mediocre with other actors. He and James Woods, IMHO, are two of the greatest living actors BECAUSE they will work in anything and try to make it better.