You’re not wrong about the downsides. However you’re wrong about the costs being prohibitive on general. I’ve personally worked on quite a few applications that do this and the additional cost has never been an issue.
Obviously context matters and there are some applications where the cost does not outweigh the benefit
I think you and the GP are probably talking about different scale orders of magnitude.
Very likely!
But I think there must also be constraints other than scale. The profit margins must also be razor thin.