Regardless of individual stock performance, present-day total stock market liquidity is a proxy for expectations of future total stock market liquidity.

If people are keeping their money in the market (regardless of allocation inside the market) they are expecting that any other asset class will perform worse in the near future. If they expect that commodities are too volatile, spending won't pay off, monies and bonds will inflate away and land may face legal risks from populist, technocratic or extrajudiciary changes to the legal system then their least worst options are to go all in on stocks. Furthermore, the energy sector is going to have a windfall from filling up the VLCCs of the world and look for anywhere to dump the cash that helps escape taxes, driving future liquidity expectations even higher.

Right, and "monies and bonds will inflate away" is related to what I said re ZIRPs -- you can't expect a decent return by parking your money with the bank, either, as interest rates are low to nonexistent. The stock market's the only good option. This was no accident, it was an intentional policy move... And now, "the DOW's over 50,000!"

What's even more troubling is that there was once the pretense that valuations had something to do with fundamentals, but this has gone entirely out the window since about 2013.

So basically none of it makes any sense and you've just got to ride the tiger.