Week 1 preseason - starters play a series
Week 2 preseason - starters play 2 series
Week 3 preseason - starters play the 1st half and hope no one gets hurt
Week 4 preseason - starters don't play at all
Assuming everyone follows this what are you really learning watching your 2's and 3's playing against another teams 2's and 3's? The majority will never see the other again, ever.
Why is there preseason football? John Madden once said any team can win a preseason game if they want to (Todd Haley not included) Madden hated preseason. No coach worth anything needs 4 games to figure out the 53 he wants for week 1.
Hell, why ever have your starters play in preseason at all and not let your 2's and 3's get some snaps against 1's to see who really has NFL talent?
It's got to be about the money.