The older age groups are difficult to manage in all sports. I can offer some personal experiences here to illustrate some of the problems involved.
Mid to late 90s I coached a team from 14s to 17s to help a friend. Each year more and more difficult to get a team on the field, each year more and more difficult to get the players that I had to training with their other committments. We made it all the way through and I loved working with the boys, but it was tough - as anyone who has done it would know.
Being a masochist, I then continued on coaching into colts. More support and the competition was better structured, so life was a bit easier. Somehow managed to be our colts rep to twice a year meetings with NSWRU. To my surprise it became obvious that some clubs considered colts to be something of a nuisance which had to be tolerated as being a condition of being in the NSWRU 1st division. They were always trying to cut the number of grades and the number of rounds played. Fortunately they were a minority, but only just. They tried to do away with 4th Grade Colts and when the majority wanted to keep it, only 7 clubs entered teams. This meant a bye almost every second week, so the next year no 4th grade colts. They were efforts to do away with 3rd Grade Colts as well.
I'd like to think that things have changed, but...