The problem is not that the kids on the higher level don't work hard. I think that when they put the kids on the new team they did not inform them until two practices in that the team had to many kids and some would not be on the team in the end. The parents haven't even heard from the gym yet about this situation they have just told the kids.
So I have to ask...
...you sound pretty upset about this. I'm assuming you're not one of the ones from the dissolving team, because it sounds like they're staying the same level and possibly displacing others that have been on that team already. But I may be wrong about that.
So, I'm guessing that you're either upset that you might be losing team mates you've bonded with for new ones which isn't sitting well, or you're concerned you will be displaced and moved down to another level.
If its the second, I would suggest looking at your total cheer package in regard to the team you're on. If you're one of the ones to get displaced, will that actually be a good thing? Will it give you a leadership role by putting you at the top of that team? Will that team be more successful with you and others displaced moved down onto it? Are you currently struggling to (or don't have all) the skills for the team you're currently assigned? If so...this might be a good thing. You can be at the top of your game with no pressure you're holding a team back, you can take time to build those skills over the year for next years evaluations and you can be the leader of the new team. If you define yourself by the "number" on your teams's division, you're not cheering for the right reasons.
That's all if you're a displaced athlete. If you're one missing a team mate, you are still at the same gym, you can still support each other and you can take this opportunity to make friends with new people too.
Being the positive person I generally am, there's always a bright side, and if the coaches haven't told parents anything then my absolute BEST advice is to stop making any assumptions (because they may not even know what they're doing yet and it may change four times before they publicize the final answer) and just have faith that what your coaches are doing is in the bet interest of you and the rest of their athletes.