Finding someone who thinks they have it all and will be the next big billionaire is easy. Finding a group of people who know what work needs to be done and can put their nose to the grindstone to match the "vision motivation and skill" is the hard part. Just look to google, the holy grail of tech visionaries. No one doubts that Page and Brin have vision/motivation/skill but they readily admit that their initial team of engineers is what carried them and they rewarded them like it.
What you're advocating probably feels good for the ego though... everyone loves imagining having demi-god-like status. For me it's always interesting to look at what people are fighting for. "The founder deserves 100 million, not 80 million, pay the engineers less!" At the end of the day it's just greed.
I do agree with your last point: engineers are often idealists and/or they have very strong preferences about what they want / don't want to work on. So they may often be willing to give up much better comp in order to satisfy such preferences. That's why startups get away with paying maybe half of what large corporations pay. Still that's not nearly enough to explain the gap between engineer and executive compensation.
That said, I sometimes feel that being a successful founder has less to do with skill and more with being at the right place at the right time.
Would be interested to see what others think.