Isn’t a large part of fundamental problem the lack of clarity and mental discipline to stay focused on MVP and if it’s clear it’s necessary then pivot but still stay focused? It seems clear to me that real problem is lack of focus and discipline.

Yes, but the subtle issue I've seen in companies is "MVP" easily ends up interpreted as: "add this one small thing since it's quick and easy to implement". Then before they know it you've got this mousetrap-like product that goes in all sorts of directions.