Beyond nepotism, there's a lot of actual learning experiences you can gain from your peers by debating them in case study lessons, working with them on projects and participating in simulations etc.
Doesn't that happen in an informal way on a lot of subreddits and even here?
This doesn't come close to describing every single professor, but I imagine (albeit without any sources to back this up right now) that the ratio of such unicorn professors is higher at Tier 1 univerities vs. non-Tier 1.
Perhaps with a larger supply of determined students willing to tackle this on their own, this is the year where a larger number of focused case-study groups could be formed and sustained online.
In theory these communities can exist online. In reality, the vast majority of online communities are not open to being a classroom setting.