Sure, but it just sucks for JMU to lose their FB coach, their BB coach and their university president within a three month period. That said, the Dukes have come a long way in short period of time, which explains why their leaders are wanted by others.
For Byington, it comes down to money. Guessing Vandy offered a 5 year guaranteed contract which probably at least quadrupled his salary. That's life changing money for Byington even if he can't ultimately turn it around in Nashville.
There are a finite number of Power Conference jobs and Byington wasn't getting the Kentucky or L'ville jobs; so, if he waits, who knows when the next power conference offer comes. Also, JMU had 5 seniors in their rotation, the Sun Belt is a one-bid league; so, if JMU regresses at all, he won't be getting any power offers for some time.
Also, Vandy isn't a great job, but Kevin Stallings (who is a douche; BTW, I just learned that Kevin Stalling's kid is a MLB player Jacob Stallings) did have it going there at one point (6 NCAAT bids between 2007 and 2016), including a sweet 16. Expectations are down in Nashville so Byington can stay for a long time if they are even moderately successful.