1. Get a funded PhD offer for 3-4 years (The funding is tax free so comparable to the average grad salary).
2. Complete in 3-4 years (it is hard to get more than a 6 month extension, technically they can take their money back if you do but this rarely happens as the system wants you to quit early or succeed).
3. Be more employable (I'm speaking from personal experience here. I didn't go looking for jobs like I did after my undergrad, they came to me via LinkedIn/Monster etc.)
As an avid reader of PhD comics I have always struggled to understand why the US system is so different.
As a side note it is worth pointing out that it is foolish to assume that doing a PhD inherently leads to a Professorship now. What it does do is give you 3-4 years experience (which employers like) and a vast range of research and communication skills (which employers love).