I know I see this over and over at our gym, and then those same parents get angry when their kid has a tumbling block. I personally think that the rush to the next skill without perfecting what a kid has contributes to mental blocks. Kids are throwing skills that are not solid, so there is an element of fear there every time, then one bad fall and they block on it.
CP has a private lesson coach that is very much perfection before progression, and you have to understand that going in and have the right mindset to be successful. Time after time I see the same thing. Kid is stuck at a certain level, cannot land that tuck, layout, full ect. They sign up for privates with him because he has a reputation for turning out top notch tumblers. They come in and expect to immediately be working the "problem skill". Instead they go back to the roundoff or handspring that has not been perfected and is causing the issue. Parent leaves in a huff because "Suzy has _____ why is she working roundoffs?" only to show back up months later still working the same skill, but now ready to listen to the coach and fix bad habits. My CP wouldn't tumble with him when we came to the gym because of this approach, and frankly I didn't understand enough to tell her different. he was trying to correct bad habits she had picked up tumbling at a dance studio and she just wanted to move on. She is older now and sees more of the big picture so it works for her. She is a stronger tumbler, and when she gets a skill, she is confident that she can throw it safely.