You can just get finished Microcontrollers that you can program yourself for a fraction of a fraction of the price to make them yourself, and orders of magnitude more capable. You will not be able to make a chip more capable than an ESP32 for less than $2, so how would making an IC yourself help you?
I imagine it would be in preparedness for a time when you could no longer get such powerful chips so cheaply and quickly, or for one where you no longer trusted the chips you could get for some reason.
