That's why you get on early. It's the same with the stock market, almost everyone starts investing when it's high and when it crashes they sell which is the exact opposite of what they should do.
I don't disagree with that. The S&P will be a very good buy when it gets back down to the 1500 area. Lots of people will be wiped out during that process. 401k's and retirement plans are loaded to the gills with these FANG stocks, which are ridiculously overvalued. Those companies will lead the market down. There will be plenty of dead-cat bounces on the way down.
The only asset not in a bubble is... gold and silver. I expect PM prices could fall even further with the market (i.e. 2008), but there will be a run to safety when the markets really start get hammered. PMs are where investors always run to in protracted bear markets. JP Morgan has accumulated the largest physical silver position in history... you think they know something?