As mentioned before Crabcake, with basketball there are only 7-10 games per night, as opposed to baseball, which has 16 almost every day. That means fewer players to choose from.

At this point, early in the season, the cap values for the players are much lower than they will be in the weeks to come. That's why everyone is able to load up on the same 3 or 4 top guys at each position every day.

Once Tim Duncan, and Tracy McGrady and Kevin Garnett, etc. have their values go up to lets say 26, 28, or 30 each, it will be impossible to have them all on the same day and still have decent players on the rest of your roster. But while the values of the top players are so low, you can take them all on a given night, and still have plenty of cap room left.