1) What kind of team would we have if everyone who didn't start, or lost their starting job, left the team unless they got their way?
We know the answer to this question. Look at the Wolford years. We had as many as 20 players quit in a single season because of the issues you note.
2) What kind of team would we have if all players sacrificed team success to avoid contact or injury?
We would be better in some cases. You make avoiding inury as a negative. Sometimes wisdom and living to fight another day are an advantage. I don't see Tom Brady diving for the extra yard like RGIII does and how is that working out for those two?