IMHO, the event that killed Vegas was 9/11. Before 9/11, it was a lot easier to win at some games over a period of 1-2 hours (especially Blackjack). After 9/11, it seemed almost impossible to come out ahead after that time. And also after 9/11 things started getting expensive.
I agree. 9/11 screwed everything up. Nothing has been the same since.