And somehow this grading scale is to produce more and better referees?
I agree there is an issue, and you have summarized one aspect of it very well, in the fact that many of the "youth" referees play in the fall. What you've also done however is take what was a legitimate question, and now turn it to a referee quality discussion again. Perhaps if all of those expert referees from the sidelines would get certified and help, we would have no issues in either quantity or quality.
It's a numbers game. With each club hosting tournaments as fund raisers, inviting out of town teams, the assignors job gets difficult. From the state perspective, it would be better to have the best referees at games where out of state teams are involved, ie tournaments and RIII. This then however depletes the various state leagues. Just like people are trying to increase the numbers of players, so should the numbers of referees.
Finally, most referees are encouraged to ask for and receive "constructive" feedback, both positive and negative. To date, I've only had 1 coach be able to provide what I have considered constructive negative feedback at the end of the match, both in tone and demeanor. Until we get away from it's okay for coaches or parents to provide a "kick in the pants", the referee shortage will not end.