Stocks are high because you have 55 million baby-boomers at retirement - who have NOT saved enough for retirement, so they are frantically dumping their money into 401K and IRA’s (stocks) regardless of what the price is or actually should be; and you have 45 million post-boomers who KNOW they will not be eligible for Social Security for some “new” reason or another that has yet to be invented ... So THEY have to dump THEIR money into 401K and IRA ...
Again, regardless of whether the stock prices are good or bad, they have no choice but to buy stock.