Jack,
I totally agree with you. At all levels it is about managing expectations, being open and transparent and pro-actively communicating.
Here is a real life example that I was part of this year.
I took over an U12 Girls team and expectations were that we would be a middle of the road team. I met with each parent and child to outline (1) my expectations of them, (2) what our goals as a group were, (3) what they could expect from me and (4) how we'd address issues.
I set out from day one focused on developing skills, turning them into habits and teaching about the game - not winning but how to deal with what the game throws at you and get better.
One key expectation, everyone would play every game. I guaranteed 25% court time every game during tournaments / the season with finals being different.
Did I make mistakes a long the way, you bet. However, next training session I walked up to the child and their parents and told them I made a mistake. No excuses, just open and honest!
Each week, I'd speak with the kids and their parents. Not every parent but some of them. We kept game records of court time and the impact the kids had on our performance (not individual stats but + / - impact on our score whilst each group was on court).
Mid year, I met with the parents and child formally and discussed how (1) they were going, (2) how the team was and (3) I felt I was going. They had a chance to have a say. We showed them the time and impact data for their child and used it to look at how they could get better.
I continually reinforced the goals, expectations and parameters. Especially just before finals at tournaments, the Classic and end of season. Sure, some parents didn't like it but everyone new the story. I even benched better kids in some games to allow others the chance to play more - even lost a game or two for the longer term goal.
Anyway, it works out the least court time a player got was 40% over the season and tournaments. In finals, everyone still played and averaged 25%. We won the Victorian State Championship when most people didn't expect us to get out of the first round of finals!!!!!
Key points - (1) everyone played, (2) everyone learnt and got better over the season, (3) everyone understood in the 4-5 big games that our focus was winning and that may need to sacrifice, and, finally, (5) we were all on the same page.
It can be done but the coach needs to lead the way, role model and constantly communicate.