Very true. How well you do on the LSAT is driven heavily by whether or not you took a prep course because the questions and exercises are weird. A lot of the course is focused on teaching you the language of the test and strategies to solve the stupid "games," and it has virtually nothing to do with law practice or study. And again, I did fairly well, but I'd never brag about it. I did well on something stupid and only did well because I could afford to take a course.
And yes, going to a fancy law school has virtually no bearing on the quality of the lawyer. One of the better lawyers I faced was a black dude who went to TSU. He worked for a crappy, ghetto insurer that consistently offered garbage, so he was almost always in court. Well, if you're always in court and are reasonably hardworking and conscientious, eventually you get good at it. I faced several from Harvard (and yes, UT) who weren't as good