the question itself is wrong. if you go for a ph.d, you must be prepared to go through the tenure track. Your only destination is become a professor. Anything other than that is a waste of your education. If you want a job, avoid ph.d asap. ph.d does not earn more than a university graduate. How much do a professor earn? Haveing a Ph.d does not guarantee you a fat paycheck. Considering your lost 3-4 years, you will never earn enough to cover the loss.
All the ph.d graduates I know has family background, either their parents or in-laws are professors in China. It is the only reason they finishes ph.d. Once a good job offer comes, can you resist the temptation? Doing ph.d is a painful experience. People always chose the easy way.
Of course, if your topic brings your commercial opportunities, you are the luckiest guy. Maybe you can start a company after graduation, like research in motion. However, most of the ph.d believe the only reason they are doing research is to get the degree. It is awful knowing you are wasting your time only producing gabage papers.