This is a rather vacuous piece, and for anyone looking to avoid wasting time, the stated reason is: "corporate profits keep going up."

I think the byline is a bit of a disingenuous sleight-of-hand: "The boom is not as untethered from reality as it may look" presupposes a majority view that the stock market "is untethered from reality," but whether or not that's an accurate read of prevailing sentiment, it subtly shifts focus away from what most people ought to understand: profits of the largest corporations are now mostly untethered from the financial health of individual citizens.

I've been seeing more and more of this type of underhanded writing from billionaire-owned media outlets lately (the number of which is growing on a nearly daily basis).

stocks go up because firms use the same algorithmic trading formulas. its very similar to how gas stations have the price sign out front to signal to nearby gas stations price fixing to engage in. we see swings of 800 points like its normal now because everyone is just on the same page even without insider trading lunches.