I don't know if there will be a crash. The market went up slowly, it could also go down slowly. That's the Fed's goal, it seems.
I do think that any time a bunch of people are making a bunch of money without knowing how or why, but by simply following the herd, it is leading to a dangerous place.
This is happening right now in the S&P 500 and other index funds. Everybody is getting the same advice ("buy index funds") and following it blindly.
I expect there will either be some kind of sea change where the herd starts moving (possibly stampeding) in the other direction, or someone on Wall Street is going to figure out how to take advantage of the movements of the herd.
But this is all speculation. If I knew for sure, I'd be a billionaire in the next few years.