Assuming we're talking travel ball, and not rec. ball (and there IS a difference)...
One stage for Rec. teams:
1) Sign up and play. Roster spots are rotated to give equal play for all
Two stages for travel ball teams:
1) Try out and make the team; the only guarantee is a roster spot
2) EARN a starting position, which garners most (or all) of the playing time
For instance, a new pitcher could "make the team", but not necessarily get much circle time as the season wears on. She'll get a chance to prove herself, but after a few games, it's usually evident to all who the #1 is. The great thing about this "system" is that it closely resembles the college ball system, which travel ball is the prep for. It gets the kids into the mindset that they must work very hard for their playing time. When coaches start a rec. ball rotation, the quality players will start a mass exodus.
If you equate a "roster spot" with "playing time", you should probably stick with rec. ball, where playing time is doled out relatively equally. The bleed over of this mentality is slowly chipping away at the meaning of travel ball.