[andrewvc]

Possibly, however the better you are the faster you work the higher your value per hour. If I can be 3x as efficient as a junior dev I'm still worth more.

[modarts]

If you are introducing bugs that will at some point need to be addressed while "working fast", that'll cut away at a lot of the added value.

[jiggy2011]

This is where experience helps. You know how to be efficient without sacrificing code quality and you also get a better intuition for tracking bugs that you do have.

[mrgordon]

Yep, and you know what to write tests for