It’s almost like there’s no connection between administrations and the stock market
That’s not true. Republican Presidencies very regularly implement large tax cuts at the beginning of their administrations. This tends to create a flow of new cash for investment, which results in speculative bubbles, which tend to resolve as market crashes 4-8 years later.
Reagan, Bush Jr, and Trump all kicked off this cycle. Even Obama is kinda-sorta guilty of it, having slashed taxes as part of the '09 rescue package and inflating a small bubble that popped in 2014. Trump’s collapse came on a bit earlier than expected, thanks to COVID, but he’d paved the way to the Crypto Crash (FTX devastated large parts of the off-book financial economy and kicked off an inflationary cycle as big finance guys scrambled to reposition) from day one of his administration.
I’d argue that the current AI bubble is in no small part a function of Biden’s over-investment in Big Tech at the expense of manufacturing and transit. But we’re still waiting to see how that pans out.
investors know they’ll make shittons of money either way
Plenty of investors ride the boom/bust cycle to their own demise. We just don’t talk about them the way we talk about the Gates and Buffets and Bezoi, who diversify thoroughly.
But what presidents direct the national budget to do absolutely matters in the downstream industry. Whether MilTech or Telecom or Construction or Agriculture or Semiconductors or Intercontinental Logistics outpaces the field depends heavily on what direction the President moves on domestic subsidies, government contracts, and international trade deals.
If Bush Sr and Clinton had told their administrations to invest big in Linux, I question whether Microsoft would be a household name. I can tell you for a fact that Exxon adopting Oracle Database Suite was what transformed Larry Ellison from small time software salesman to billionaire. That came on the heels of the Reagan DOJ fucking over Inslaw, Inc (which was on the forefront of relational database tech) and trafficking the PROMIS database engine to partisan insiders like Ellison (former CIA contractor) and Perot (oil industry flak).
We’re seeing the modern incarnation of this with guys like Thiel and Musk, who are cleaning up on government contracts in information security, automotive subsidies, and aerospace technology largely by buying out the competition with cheap loans sourced through Federal Reserve friendly private banks.
Presidents (and their downstream cronies) have enormous influence on which businesses and industries succeed and which ones fail.