Inertia, being carried by past success, delivering juuust enough new value that their clients don't switch away from them.

Or their clients have inertia and continue to use their product long past the time they should have moved to a competitor who is innovating.

I don't know. I think there's a lot of dead weight in the big corporations that is being carried along. I think you can see this a lot in marketing departments with massive budgets. They spend their money marketing to other big companies. Those companies are spending their money marketing back to them. It's like a shell game where a lot of money is moving but nothing changes.