On the risk of being labeled as "CMAS biggest fan" (although certain people here are blind to any critical note I also have on them), I think it is unfair to say that CMAS is prinicpally against running u19 comps.

During a meeting we once had with Ferero he said there is no problem holding U19 comps when there are 10 countries or more participating. The only problem is that we don't get to 10.
Of course this is kind of a vicious circle. Not many countries will be motivated on getting a team together when there is no championship they can grow.
In finswimming it is easy to have 10 countries as you only need 1 athlete from each.

Furthermore, comparing uwh with other sports is very tricky. As Carol says, we can't really compare ourselves with sports that are fully developed. Also Ferero needs to understand he is not running f*cking FIFA (international soccer ass).
Nore can we keep looking back at the past and say "but we have always done it that way".
Truth is that uwh is in its adolescent phase. There IS no more room to have elite, U19 and Masters all at the same time. We can have them at the same venue consecutively if we want, but mixing everything has become impossible.
Sheffield was an extrodinary champ, but would have avoided nagging from countries etc if the elite had been in one week and masters and juniors in the other.

The split, however, has created an unexpected turbulence we must pass before focusing on the further growth of our lovely sport to adultary.