Money is what keeps it going, if you just want to look at the # of transistors. The problem is that the advantages of modern process "scaling" have stopped being advantageous except for a few uses, and profitable for very few (one) producers. That will shrink investment in new Fabs. We may be at the last hurrah, unless something (AI?) really pops to keep demand up for more expensive transistors, or there's more government subsidy.

As a fundamental scaling law Dennard (supporting Moore) has already collapsed. Speed stopped scaling with node in the early 2000s, Power stopped in the mid 2000s, and cost per transistor before 2020. Cost per transistor is really critical, because you have to justify more complex designs when they aren't actually cheaper to make (as they have been every year for over 50 years).

   https://en.wikipedia.org/wiki/Dennard_scaling
   You used to get -50% cost&area reduction, -50% power reduction, +40% performance
   For each node (0.7x dimension scaling).

From the article, "Samsung’s 2nm (SF2) process has shown a 12% increase in performance, a 25% increase in power efficiency, and a 5% decrease in area, when compared to its 3nm process (SF3)." Estimates on cost/transistor are ~50% increase for SF2 due to layer count, yield, and production costs. The biggest improvement in transistor cost is now Fab amortization, but that only counts if the Foundry is overall profitable in the first few years. Otherwise, it's just a sunk cost born by stockholders, banks, and governments.

There's lots of other stuff like die/wafer stacking and more complex multi-chip modules (including optical/RF), but those all add significantly to complexity with marginal cost improvement. You need the payoff to be obvious or the bean counters stop giving you beans. So far momentum is carrying the investment, but a failure (eg Intel) could really cut that off.