More work, higher rates, better clients

Benefits accrue to those willing to dig deep, and produce work to spec.

And it’s not just because you get more gigs at higher price points.

It’s because the more opportunities you have to put on a show, the more chances you’ll get to learn something while you’re there. The more you learn, the better you’ll get, and so the more you’ll get to charge.

At the same time, more people will see you on stage, and so demand for you and your work will increase, so that, over time, you can begin to work with and for better clients.

Do it long enough, and you might even get to choose your own. (Quality) work begets (better) work, as they say.

The converse works much the same way, only in reverse. Mediocrity leads to less gigs, less pay, and yes, poor clients. From that point of view, it's hard to see why you would even consider slacking off.