Competition and general bandwidth for attention is simply too intense when you are one of more of the following; 1. Adult, 2. Parent, 3. Gainfully employed, 4. Property owner, 5. Business owner, 6. develop serious interests outside of sports.
When you have zero, or next to zero responsibilities, you can recall 25 man rosters, lineups, league leaders, etc. It's not possible once you possess one of the aforementioned traits.