No, it's not. Engineers figure out what to use based on availability, target Bill of Materials cost, schedule and performance needed. If the Pi hits those perfectly, then you use the pi. If not, use something else.

In many cases, meeting a development schedule is far, far more important than cost or other constraints. I will happily throw a $25 ESP32 module at something that a $0.50 Atmel chip could handle, if I only need to build one unit. The $25 is a bargain compared to the amount of work I'd have to do to get the Atmel chip up and running.

aside from how high the labor cost for that would be