I hear you, but this isn't that uncommon in the real world. There are people hired all the time to take companies from one stage of their development to another. They're hired with the understanding that their job is to get the employees to change their mindset from A to B and start working toward new goals using different resources. They often stay on for two years or less.
Greg Cronin is 60-something. He's never had an NHL head coaching job. I can easily imagine this scenario: Pat Verbeek says, "Here's a two-year contract** to coach an NHL team. Your job is to get these kids to work hard, develop good practice habits, and learn the defensive side of the game. Wins and losses are secondary. At the end of those two years, we'll evaluate the progress, but it may be someone else to get this team to the next level." If you're Cronin, you still take that, right? You bet on yourself and hope that you can impress Verbeek enough to stay on, or, if he doesn't keep you, he'll at least recommend you to other franchises.
And as for a new coach, the culture Cronin's setting will work with anyone who comes in. It's not like the next head coach is going to be upset that everyone is practicing hard and backchecking consistently.
** Do we know what the length of Cronin's contract is? I assumed it was two years and that Verbeek wouldn't actually have to fire him after the season. Cronin could just be let go. But I don't know for sure.