Giving a coach a 10 year contract is nuts. Where has that ever worked out?
No one can look 10 years into the future. People change. Especially when you are talking about a person as young as McVay who isn't married yet, has no kids yet. Circumstances change as well.
Giving a coach a 5 year deal is the longest that should ever happen and you only do that when there's also a way to protect yourself. In fact, I doubt that a 10 year deal would be of interest to either party.
Might McVay deserve a raise? Might he deserve a new contract (or extend his current one)? It would be hard to argue against.