Someone has to be looking at where the business is going. In most small firms that person is also the busiest one doing the work, so nobody is doing it.
The metaphor is simple: a ship needs someone at the wheel watching the horizon, and it needs people rowing. The owner of a small business is usually rowing hardest of all.
The consequence is not that the rowing is bad. It is that the ship makes excellent speed in whatever direction it was last pointed, and nobody notices for a long time that it is the wrong one.
Gerber's version of this is working *in* the business rather than *on* it — see Michael Gerber. The ship version makes the same point about direction rather than about systems.
Not 'are you working hard' but 'when did you last spend two hours deciding where this is going, with nothing else in the diary'. For most owners the honest answer is measured in months.