Depending on your definition of cheap, fab access might be pretty cheap right now for old technology nodes, which have totally reasonable performance if you have an architectural advantage.

This article suggests mask tapeout costs are under $1 million in older nodes, sometimes well under. If you have an architectural advantage in a problem domain with tens of millions or more in costs, a simple ASIC can be very worthwhile. That architectural advantage might be hard to find, especially when problem domains aren't fixed for long periods of time (e.g. how many ML accelerators only really work well for dense convolutions?), but I suspect too few companies are making custom chips, rather than too many.

https://www.electronicdesign.com/technologies/embedded-revol...