I am willing to bet that they are not “sailing through”. Elite is a beast and it’s never an easy ride.
Remember social media always presents the sanitised, best face. People will post “woohoo, got x skill” alongside a neat, well executed video. They don’t post the 440 times before it went wrong, the tears and frustation, the wanting to quit because they can’t do it, the physical aches and pains, the growth spurt that means it all went wrong again after being so close.
It is very hard not to look at others and see them learning new stuff, progressing at a seemingly warp speed. It is difficult not to compare and see your child being left behind, dropping off the radar. But every child will have peaks and troughs. Focus on the small steps your child is making.
Mine has pretty much repeated the last 3 years. She was way ahead of the field at 11, but various reasons have meant she’s not visibly progressed. Others seem to have caught her up and stormed past, and they are the ones people are talking about and focussing one. However i know they have not had it easy, at all. Dd is at least happy, and a new coach and things seem to be clicking into place. She’s got 4 years now to take it slow and build on that, while the others have to stay with the high training hours and injuries to improve.
It’s the long game. Tough in this seemingly short sport where the thinking seems to be if they aren’t world class the day they turn senior they won’t get there. But with the right coach they can and do. There are probably far more slow developers have a senior career than the young bright stars who burn out last year of junior.