It's not insane. The GP is correctly describing a bubble economy.

The money chasing investments is orders of magnitude larger than the money people have on their pockets to spend. As a consequence, the only profitable thing to do is sell capital goods to make business and there is no profit on selling actually useful things.

China is in a different reality in large part because of their capital barriers that stop money from flowing in. Countries with bad reputation are also less affected.

What the GP gets wrong is that none of this makes AI a good business. Instead, it makes Nvidia a good business, but that's not news.