The former Everton captain, who has since retired from football, was part of the recently-departed Stuart Pearce's coaching team for England's campaign in the Under-21 European Championships in Israel.
The Young Lions were knocked out of the summer competition in the group phase, failing to gain a single point during the tournament.
"Our Under-21 players aren't playing enough quality football early enough," Sky Sports News quotes Neville as saying. "I got my experience at 18. Our lads now are 21, 22, 23 and a lot of them still aren't playing and getting the rigours of 40 or 50 games a season.
"When I was 21, I'd travelled the world playing football, playing three games a week, so my body and mind were battle-hardened. A lot of the kids now aren't battle-hardened until they get to 27, and that's too late. We'll have missed another generation of international footballers."