Passing the bar does not "prove you deserve a career" in law to more or less the same degree that getting a PhD does not "prove you deserve a career" in academics. Plenty of lawyers who pass the bar (these days) ultimately are not successful as lawyers, and the low levels of attorneys at big law firms are a grind designed to weed people out in much the same way that tenure tracks are.

Ditto finance.

That's not to say that either law or finance take AS long as academics do to get to the point where you're secure in your position, but neither get it right out of their degrees.