50:50 would imply that 1 in 2 PhDs would get tenure; the odds were never that good.
One thing I can't understand is why are people not researching this kind of stuff beforehand? By the time you're doing a PhD you're in your mid to late 20's right? You should've been thinking about your marketable skills since you turned 20. You can't just do whatever you like and expect the world to throw jobs at you.
[1] This data is cited above.