How long can it go on that the single most decisive factor rises, interest rates, and the markets nevertheless climb higher and higher?

One thought: perhaps quite a bit longer this time around than in past episodes.

The three step reasoning for that:
The idea behind raising short term interest rates is that it will dampen both speculation and business investment with low marginal returns.
At the moment the US economy's growth is *hugely* dependent on the AI crowd and their suppliers, and the trickle down from that spending.
Those primary actors aren't at all interest rate sensitive, so higher short term rates will not have any direct effect on their investment plans.

(Only very indirectly, if it gets to the point that they actually have to cancel something because they simply can't sell the bonds or equity to fund it, or the high rates have killed other actors in markets so much that their revenue projections get revised downwards)

These folks are borrowing so much without regard to pricing that they are starting to dominate some bond markets: other yields are rising in part because that's what the big AI deals are paying, so others have to pay that much too. I think AI bonds are something like half of the CHF bond market lately.

So...make hay while the sun shines.

Jim