Greed? No, it was all about taxation.
The founders were all rich. Some more than others. High moral ideology might have been a convenient adjunct but the stated purpose (all that really counts) was taxes. Unlikely they would have formed a new country over anything else, just not immediate or weighty enough.
I think you're looking back from a position of modern comfort and doing so with unrealistic expectations. Life was hard in the 1600's-1700's. Everyone had ten kids just to make sure they ended up with two that'd live long enough to give them grandkids. Most people worked jobs that directly supported their life. People died just from seeing the dentist. Oppressive taxation was much more serious.