totally...look around at all the people searching for something to fill the emptiness in their lives...they fill it with the "empty calories" of consumerism (oooh, i need a roomba!), and distraction (oooh, celebrity drama fight is on!). as you said, we evolved having to hunt, having to survive, and now, since the first few rungs of maslow's hierarchy of needs has been met, since we don't have to worry about getting eaten by animals or starving, we need something to keep us going. the human body seems to be one of the few, if not the only, machine that gets better and stronger and lasts longer the harder it is worked and used.

mountain biking helps give us what we need.

oh, and to ramble on some more...

the focus and concentration, the singleminded-ness you get, not riding a bike but you and the bike as one entity riding the earth, when you are flowing like water down the trail, effortlessly, feeling the ground below you, feeling the rise and dips of the earth, railing a berm, when you are "in the zone," i believe, is the equivalent of "enlightenment." or at least a poor mans version of enlightenment....