You notice the names of the schools that professors come from? T14 schools disproportionately produce clerks and legal scholars, so the high-level theory classes are directly relevant to what many T14 students want. But the high-level finance courses are DIRECTLY relevant to the practice of law. What you don't seem to get is that T14 and T4 schools are producing students not just for different pay scales, but for completely different legal industries.
Sure, there's only one bar exam for both "industries" -- but that bar exam is mostly irrelevant for biglaw/boutiques and directly relevant for small-time lawyer/late night TV ad personal injury law. We don't study it because we use most of it for one test, and then never again.
You also will likely never see Durden in the courtroom. IF
he chooses to practice litigation (only a part of the law -- we didn't all decide to go to law school after watching a few episodes of "The Practice") and IF
the case reaches a courtroom without settlement or pretrial disposition, he likely won't be in your county district court shuffling traffic tickets. IF
you happen to show up in the same courtroom, just know that T14 students all have clinics, externships, legal writing classes, trial classes, mock trial, and moot court too. So I have no idea why you think you'll be able to run circles around them in a courtroom.
Also, firms usually pay for that "few extra thousand dollars" in bar prep.