It's far easier to be the person writing and enforcing policies and procedures than it is to be the one who must accomplish something within the bounds of all of those policies.
At the last startup I worked for, management loved to hire heavy-hitters from big companies. Almost universally, they spent more time writing proposals, calling meetings, soliciting approvals, and gathering input than they did working on actual solutions. Not surprisingly, they accomplished very little and had a hard time keeping up with the demanding schedules of a startup.
Within a big company, it would be easy to mistake all of this bureaucratic churn and superfluous paperwork for progress and hard work. In a startup, it becomes obvious to all that it is anything but progress.