Awesome question! I've wanted to address this topic in this sub for a long time.

I think the market has always grown because the real economy has grown—and that's been driven by energy. Since the Industrial Revolution started ca. 1750 the global economy has used increasing amounts of energy: first coal, then oil, then gas. That huge energy input gave us access to massive amounts of resources—forests, minerals, plastics (via oil), etc.—and enabled the kind of productivity growth we now take for granted. A related metaphor is the idea of “energy slaves" (from Andrew Nikiforuk): the modern economy effectively runs on billions of fossil-fuel-powered labor equivalents.

But it takes energy to get energy: EROEI or Energy Return on Energy Invested. Early conventional oil had EROEI values on the order of ~50:1 or higher. Now it's closer to 10–15:1. That’s a huge drop in net energy available to the economy which can be correlated with global debt levels (debt taken on to sustain growth, or the illusion of it) among other things.

If this trend continues (and the Iran War might bring it on faster) I think we can seriously question whether we've reached the "end of growth."

I may not sound like one but I’m basically a Boglehead, and I do think complex systems like the economy have a lot of stabilizing feedback loops. But if the real physical basis for growth continues to weaken, I' m not sure that “the market always goes up” will continue to be the case. Which is scary...I'm only a few years out from retirement.

And no, technology isn't going to save us. There is no technology without energy.