Different sport. I would put a lot of that down to their bowling action. Also, as a young bowler, to be as fast as you can is usually the goal. It's generally not until you learn that speed doesn't necessarily get wickets, comes with age and experience. Not many 28-30 year old quicks trying to knock your head off. Not saying you can't name players (i.e. Mitch Johnson, Andrew Flintoff, Brett Lee) who got quicker with age or stayed at a similar pace throughout their career but most of the greats slowed down and used their nouse (i.e. Allan Donald, Curtly Ambrose, Glenn McGrath).