> It is a massively self-evident fact that a lot more money was made during the “principles” period than after.

Is it though? I've seen a lot of claims about this or that management style or company structure to be responsible for huge profits and growth. It's usually a more simple explanation, such as market timing + smart people. Ultimately it's survivor bias. It could be argued that if this were really the case, all top companies would be using it by now.