This is a really interesting thread, especially as we do it so different here in the UK.
Here in the UK we have Senior Open and Senior ALL LEVELS. Ie you can have a senior open level 1. At some comps they combine senior open and senior if the categories are small but due to universities mainly competing in allstar senior open divisions the open divisions remain consistent. Also senior divisions do not have a top age bracket, only requirement that one person is over 16/17years to make the whole team senior, open is all athletes over 17years.
For us here it works really well allowing 18+ athletes to compete at a level which is appropriate. Uni's rarely take on girls with cheer experience (but this is changing) so to throw them in at 6 would be dangerous. But even those who have competed at a younger age and want to continue are not necessarily at a level which allows them to compete 6.
I think it is really easy to forget that many people accept that they are never going to compete at worlds, or throw their double but are just as passionate about the sport as the top dogs (Maddie, Gabi, Erica etc).
I am by no means condoning dangerous level 6 routines but if level 6 is their only option at the moment and they only throw one back tuck basket don’t come down too hard. I bet they know they are sure as hell not maxing out, but I am positive their weekly training and sense of achievement is a welcome distraction from the mundaneness of every day grown up life ;-)