AI Solution to Cultural Drift?
On reflection, I am now a bit more optimistic about solving cultural drift, *if* we can get broadly human-level AI, or ems, before our current civilization falls. My hope is that while most folks seem strongly against letting capitalism control a lot more of our human world, they seem to be more okay with letting capitalism control much of the world of AIs. Capitalism can plausibly drive cultural evolution strongly enough to end cultural drift.
Two scenarios could block this: we might either love or hate AIs too much. If people love AI too much, they might seek to give AIs many rights and protections, including “protecting” them from capitalism in many of the ways that humans are protected.
On the other hand, people might hate AI too much, fearing that it will kill us all if allowed too much freedom to choose its own culture. They might instead make and enforce laws requiring AI to be “aligned” via slaving AI to human culture, and thereby preventing capitalism from evolving more adaptive AI cultures.
So the sweet spot is a middle attitude: seeing AIs as okay but neither sacred nor Satanic. For once muddling through, instead of being principled, might be just what the world needs.

>preventing capitalism from evolving more adaptive AI cultures
Why on earth would we want “more adaptive” AI cultures, insofar as the obvious adaptation would be to cut us out of the loop altogether.
So much conflation of the word "adaptive"! Usually you conflate adaptiveness of a culture itself (ability of the culture to spread itself through either memetic or reproductive means) with the DNA genetic adaptiveness a culture confers upon its members (ability of a culture to cause its human members to reproduce and survive more.)
But here you're conflating a couple more things: adaptiveness of an AI for capitalism (i.e. ability of the AI to generate profit for its owner, and thereby cause itself to be copied and run on more computers), and adaptiveness of an AI for human culture (which could be either of the previously mentioned conflated senses!)
The elephant in the room is that capitalism is highly maladaptive for the DNA genetic adaptiveness of its human members. Modern capitalist cultures have dramatically lower birth rates. Companies push employees to maximize profit for the company, to the exclusion of social and family life. And they use marketing to cause customers to desire their material products more, which competes with the desire to have and raise children.