Exactly. Grad school is no place for smart people. For the most part anyway. There are still a few outstanding professors left in academia. You can easily find them these days because their courses are freely available on the Internet. You can evaluate their thinking style and their interests in a matter of hours.
Brian Caffo at Hopkins is a shining example. He even shares concrete guidance for working with him on his website, including what he expects from student laborers and what they can expect in the process.
The only problem with great mentors, however, is that they are often exceptional relative to other faculty. Is tolerating program bs worth it to have access to this one person? Not when program enrollment is no longer required to access them.
If only it were possible to make fully informed decisions about grad school 20 years ago…