Strongly disagree on distraction being the cause.
I spent a lot of time around potential geniuses growing up, and what sticks out to me is how many of them had their lives all planned out by the adults around them before they were in middle school. If anything, I think the lack of those people is because we've decided original thought isn't a virtue in our geniuses: We'd rather stick them in labs and use them tweaking models than give them the time and resources to explore on their own.
They're also identified and sheltered early enough that some of them don't develop resiliency + become dependent on the accolades they get, which also pushes them towards taking safer options. Big, creative genius disrupts things, and we train our gifted to not rock the boat. Even trying to found a unicorn company and going the VC route to become rich has a 'set path' at this point.
I also would doubt our young Newtons and Einsteins are spending much time on TT, unless they're studying it. It gets repetitive pretty quickly if you have the insight to start figuring out how it works, which those kids would. Genius kids' hobbies tend to differ from their peers'.