Spot has correctly stated that it is very possible for weak players to get playing time -- just not on a playoff bound team.
Spot, the problem here is you are comparing apples and oranges. In your post 32 above, you talk about how teams have different goals and levels of competitiveness/ruthlessness. That is true.
So let's not talk about teams that are playing for fun, are playing up, are not interested in playoffs. Let's confine ourselves to the teams hoping to advance. In our area, I would imagine that the top 1/3 of teams each season are realistically hoping to win the flight and advance.
Now, Tennislink is down at the moment, but I would expect that when I check 2012 results, I will see that the top team edged the second-place team by 1-2 courts.
If you know that dropping 1-2 extra courts over the course of the season could prevent you from advancing, you will do line-ups to make sure you win as many courts as possible. Against strong teams, you will play your strongest players.
What do you do against weak teams?
Well, that is where things get tricky. In a team wins league, it is not hard. I will put out my stars on three courts and put four weak players in for doubles. I might even "sacrifice" one of the weak pairs on Court One, just to make sure my strong players win. That means I can safely put my weak players in the line-up against the bottom 1/3 of teams.
In an individual wins league, I simply cannot do that. I will have to play the weak players twice to qualify them for sectionals. So I will sneak them in somewhere, probably with a strong partner who can carry them against a weak team. Instead of putting out four weak players, I can only put out two. So my weak players don't get as many chances to play.
I was on an individual wins team a few years back, and it was bound and determined to advance. I was weak. I played exactly one match with a strong partner (and received one default win). I am not complaining -- I knew the team goal going in.
But since I paid $75 to register, that was one awfully expensive match.
-- Random Error Generator, Version 4.0
-- Master Moonballer