Five points of clarification regarding the “technology stagnation” hypothesis:
It posits a slowdown relative to peak growth rates of ~100 years ago. It doesn’t mean growth has gone to zero, and it doesn’t even mean that growth has slowed to where it was before the Industrial Revolution. (I said this in the original post but it bears repeating.)
It is about the technological frontier and economic development in advanced countries. It’s not about global development, which has not, as far as I know, been stagnating. The last fifty years have been fantastic for India and China, for example.
It is about technology and economics, not science. Or at least, scientific stagnation is a separate question, and one that I have a much less informed opinion about, and have not weighed in on. There is widespread discussion about physics being “stuck”, but biology seems to be making progress from what I can tell.
It is descriptive and backwards-looking. It is a hypothesis about the past, not a prediction for the future. And it is unrelated to optimism or pessimism. It is compatible with believing that slow growth is:
inevitable and permanent (Gordon)
a failing on the part of our culture that we need to correct (which is the impression I get from Thiel)
It does not posit a cause, and certainly not a single, central, grand cause. It’s just descriptive: has progress slowed? There could be multiple causes. I tend to think it is a combination of the centralization and bureaucratization of research funding, over-regulation, and cultural attitudes turning against progress (not that these are unrelated).