I don't.
I'm late 40s, kids, career....and the closest track is probably 2 hours from me (no time). I'm a single dad, work long hours....I just can't make it all fit in my life. Also, a skull shattering crash in my 20's slowed my motivation a lot.
That said, I visit the forum 5x a day, relentlessly follow the sport, watch every race I possibly can, and have to stop and talk to every guy at the gas station with a bike in the truck.
It bums me out that I'm not getting any younger and truly miss riding (raced competitively from 5y to about 15y of age, then trail rode through my 20s)...but I just can't seem to make it work in my life.
Anyone else?