How did sudoku get so big?

i like IQ tests and sometimes crossword puzzles and i like to watch jeopardy and stuff like that but this Sudoku shit, what the hell?  i see this every week in TVguide and espn the magazine has a puzzle or whatever the hell it is .I was in a bookstore the other day and there are like 8 billion of these books. how many times can you fill in stupid ass squares with #s or letters before it gets repetetive and boring? there are only 9 letters or numbers each puzzle how many friggin times can you possibly do this stupid shit? plus whats the point?  i dont get it anyone get it?