This is something I have thought about for quite a while now. One of the main things that Geno and former players have admitted is that his coaching strategies (being hard on players to get the best out of them) is one of the things that has made UCONN alum so successful when going pro. However over time, the way that players have been raised when they're younger is different, players are a lot 'softer' now and most people can't handle that kind of coaching method.
Simon Sinek did a great talk about it that you can find on YouTube if you search 'Simon Sinek millennials' (it's about 15-16 minutes long), now although that talk was about CEO's of companies not knowing how to treat young employees, I feel the message is very similar. The way that this generation has been raised is very different to previous generations, so throwing them into a completely new environment with a coach that is hard on them just is not going to work for most kids. Although Geno has proved himself to be one of best coaches to ever coach women's basketball, I can't help but feel like over time, the way that kids need to be coached has evolved but Geno's coaching style has not.