"as fast as you can" has different meanings for different people.
By my interpretation is that it means to a certain extent sacrificing career/friends/parties/social life to train/sleep/eat well. While the highs are higher than training for "fun", the lows are lower from failures/injuries/realisation sacrifices have been for limited success. Of course that perspective won't get you very far if taken too far. The big names still being successful in to their 30s seem to have the formula right to go as fast as they can but keeping it fun: (eg Farrah, Willis, Rupp, Flanagan, Linden, Simpson)
Personally I prefer the middle ground given I don't have the ability to go to the olympics. But sacrificing after work beers, being in bed by midnight on the weekends, and skipping fast-food/sugar drinks in order to still be competitive / chasing PBs is the perfect middle ground for me. Again, not quite the highs of the pros, but lows not nearly as bad either.