When you can see a path to something great, you get an almost unstoppable energy.

When you don't see a path to something great, you're an order of magnitude less motivated.

Large organizations, by their very nature, have constrained paths to greatness.

The naturally-occurring eddies of interpersonal coordination slow down any clear shots.

That means that in large organizations, there are few obvious paths to greatness, and it's harder to get intrinsically excited and in your unstoppable flow state.

That's not to say that the person can't do it, just that they can't see their potential in that context.