Not every girl on our team has them, but most. They are just hard for some kids. Long legs, weak core or lack of flexibility seem to be the catchers.
Our gym starts with lots of stalder rolls and handstands in preteam (age4-6) along with a significant amount of core work and basic conditioning that intensifies quickly as the move to team. They still have a whole rolling to handstand sequence they do as part of warmup on most days. I am not a coach but this seems a related movement. In first year of team, they start building on this with straddle holds and pushing to handstand from feet on the ground and then putting it all together. Coming down with control seems very difficult for most.
My dd is now nine and in a group that consists of levels 5-7 and the other day did eleven in a row. She is the best at them in her gym. Her goal for this season is fifteen. Every kid has their thing, right? She finds it difficult to do more than a handful of chin-ups so who knows.
All the TOPS strength stuff is part of our program but they don't have the girls compete, although there has been fleeting talk of a few giving it a go next year. Because our gym doesn't compete TOPS, it doesn't seem there is need for them to have ten presses by the time they are eight.
Most girls at her level can do 6-8 disconnected and may be able to string a few together. There are some who have been working on them for years and still don't even have one. I am seeing though that these girls who simply can't get them are the same ones that are starting to have trouble keeping up with the intensity of conditioning and training the tougher skills. They work on them every practice as part of conditioning.
My dd has been working on pike press now and still has trouble getting her toes through. Pike flexibility isn't her most flexible part so she struggles with getting flat enough.
It seems that this is a skill that progressions and strength training for should start early as it is difficult to learn and will only get tougher the bigger you get. To me, a gym where most of the girls can do them would be one indicator that the gym has a good conditioning program.