It's probably a bit of both. The US is ahead of just about everyone else in women's athletics simply because there have been more opportunities for longer. We also do have a pretty robust youth system, as imperfect as it is.
Donovan does have a point, though he is painting with a broad brush. I basically live in the (girls) club soccer world these days and there certainly are a number of soccer clubs who basically sell the idea of winning to parents. Those clubs typically teach their kids at a young age how to "win" the game. For those familiar with soccer, that basically means they teach their players how to sit in a low block, be physical, and send long balls to the other side. It's tough for anyone to score against a low block, much less 8-9-10 year-olds or any youth player. So the club "wins" the game or the tournament. The kids get a medal. The parents get to post on social media about how great their kid is....but those kids don't learn how to play.
There are clubs who approach things differently, but they are definitely in the minority. They'll focus on developing technical ability at a young age and implement tactics, formation, etc., as the players get older and more physically mature. You might see these teams lose a bunch in the younger years, but the tide starts to switch at older age groups because they've learned how to play and can think about the game and not simply how to pass from A-to-B-to-C. They teach technique, concepts, and ideas to the young kids and it tends to pay off later.
The other aspect of all of this is financial. It's expensive to play in these clubs, regardless of which version you find yourself in. But in my experience and to my knowledge, the cost aspect doesn't exclude as many kids as some want you to believe. There are plenty of scholarship/funding sources or flat-our fee waivers for players who otherwise wouldn't be able to afford to play at a club. There are scouts for the clubs who recruit promising players.
It's certainly not a perfect structure for men's or women's soccer, but changing the most prevalent approach is a pretty tall task because "winning" right now is very appealing and patience, as virtuous as it is, seems to be in short supply. Donovan's point about the rate of development for young US players as a whole is well made. I don't think there's much argument there.
There's a lot to unpack, but that's a Reader's Digest version from my point of view.