IMO, the goal is for him to have to struggle periodically with challenges he finds intrinsically rewarding. Curiosity, self-efficacy, and continuous self-improvement are all important goals.
For example, he started learning his second language last year and is now, according to his teacher, around the top of his class among children with 4 years of experience. Last year required real effort, and he had moments of frustration and feeling like he was "behind", and that required gentle conversations about setting small goals and putting in reasonable, sustained effort.
I was pleased to see him build inner resolve and focus on valuing his own progress, irrespective of how others are doing. To me, that's an important life lesson, as is the executive skill of planning and executing on the plan, which so many gifties never have to learn early.
I think this is great!
I've been thinking about what I'd like to see PG kids get out of school... and yeah, because of how school is set up, there's no amount of grade skipping that will make school finally be a challenge at the right level, happily ever after. Matilda may have lost her psychic powers because she was finally in the right class, but if such a thing existed in real life, she would likely have gotten them back after the book ended. PG people catch up to accommodate the intellectual demands that are placed on them.
I had a friend who skipped a grade and went to a prestigious math/science magnet high school, and when I met him (his senior year of college), he was still having nightmares almost every night about being attacked by a gigantic horde of monsters that were extremely easy to defeat - the part that made it a nightmare was that there were just so
many of them, and defeating one didn't make a difference. He'd never been "challenged" in classwork, difficulty-wise; in fact, I'm not sure that would have really had a meaning for him.
I wish I could have learned the lesson aquinas's son learned from the foreign language experience earlier than the second half of college (when I changed majors and had to skip prerequisites/take classes out of order, which made some classes
actually fun in the beginning). I'd been afraid of "hitting the wall" and not having the proper foundation and being shown up by all the other students who did, who were probably "so much smarter" than me. I wish I'd known that taking a class I was not technically ready for would be appropriate for me, and that not being "ready" for it was what would make it fun. (My university had a registration system that didn't check whether you had the prerequisites, which was how I got away with this.)
(I
did hit the wall my senior year of college, but it wasn't because the work was "too hard"; it was because my mental health collapsed and I wasn't able to make myself do the work. This was the limiting factor in my educational attainment.)
I also wish I'd gotten to understand what it's like to work on novel problems/projects earlier; this doesn't really have the same problem for a PG individual that regular classwork does, because there is basically no ceiling on it.
