I'm not sure where to stand on this statement so I can only sit back and watch: I thought we would meet another AI winter ~2015 when we saturated computer vision and classification problems - then things started taking off for a little bit but settled but then things really took off...

You're still likely right as things must always come down but what if it doesn't.

This is part of the answer.

The clearer answer is: the US stock market is denominated in dollars.

If dollars devalue, then the price of real assets and equities in dollars increases (i.e. equivalent value, different number).

It's entirely possible two things happen at once: (1) US companies become less profitable and competitive due to tariffs (thereby decreasing their objective value) & (2) US dollars devalue (thereby increasing assets value in terms of US dollars).

Realistically, persistent inflation, international willingness to buy US government debt, and/or consumer confidence will be the things that collapse everything. (Or not)

How long before treasury directly starts buying private shares in companies owned by the politically connected? This unsophisticated, banana republic grifting that Americans used to deride 3rd-world countries for.

Or the Intel setup, where the government simply bullies its way into an equity stake by reclassifying already agreed grant payments.

because the stock market liked his actions or the economic responses, as billionaires would make bank on any stock market increase, as would everyman's retirement account.