How much difference is there between those who entered industry after their masters and those who hold doctorates? I personally haven't encountered much of a difference as a masters holder (spent 4 years in graduate school though, 2 to finish the masters, and 2 in a math PhD program before leaving), but I also haven't worked with many PhD holders.
My experience: not all masters degree holders are created equal.
There's a big difference between people who leave a funded phd program early with a masters, and people who enroll in a terminal masters program. Especially if the terminal masters program was a "professional", non-thesis program.
But there's much less difference between people who leave a Ph.D. early with a masters and those who stick it out.