I agree with others so far in that good is so very subjective. Good to me means that that particular gymnast has given a solid effort on that particular event, at that meet, on that day, in whatever life context she is performing in. It is irrespective of anything that anyone else is doing. That holds true for a kid getting a personal best of 9.875 and a kid that finally did a bhs on beam after 3 years of fear but only scored a 7.5.
Optional gymnastics is not easier or more lax, but the kids have grown into the sport by then. They are developing strengths and weaknesses, have more body control, and many form issues have worked themselves out or they simply wouldn't have progressed that far. Keep in mind that things can change so much over the course of 4-10 years as skills start to click and as the requirements change. My kid made her handstand once in level 5 beam, and now beam is by far her best event, along with bars which were decidedly "meh" then. Vault was The.Worst. until her second year of L10 and then suddenly she was scoring 9.5s consistently. When we started out, I was sure she'd be a floor kid because she was so pretty and scored so well, but she didn't really have to tumble. She's still very pretty, but unfortunately the skills now require a power that she just doesn't have enough of.
We all want to see "high" scores, or have our kid cross the finish line first, or score the most goals. I do, too. But what's cool about gymnastics is that you will very likely never see a 40.00 AA, because even the best still make mistakes.