I've repeatedly seen the pain of people who do well in consultancies but then go off and get leadership roles at a single company. As a general rule, they are horrible leaders. They'll talk well, make up pretty reports, build elegant org structures that also make up pretty reports, give awesome names to processes that sound like they'd make a real difference... they look and sound like great execs. But they never quite grasp what needs to happen to actually make the business work. So those of us under them make it work despite all the fluff they layer on top of us.
Part of it is that they never learned what truly mattered. They have experience swooping in, fixing one pain point, and leaving. They never have to live with the long-term consequences of their decisions. So they never learned what to look for and what to seek or avoid. They never learned depth. They learned how to make a project look shiny for 6-18 months. How it impacted business in 5-7 years wasn't "in scope".
Obviously, this is all generalizations. I'm sure there are exceptional people who came from that environment. But that is exactly what they are - the exceptions to the rule.