Culturally, somehow, we forgot something that was key.
Humanity builds on the successes of the past, but the contribution to that cumulative value by each individual was brought about by the motivation of that individual, by the effort of that individual, and that individual deserves to be rewarded for the value of their individual contribution.
So for the road builder... yes, we all use the roads - thank you very much. Did you get paid for your individual contribution to that? Yes? Great. Is your effort an investment worthy of taking part in the commerce of every entity using that road? No. Your reward is for the effort in building the road. You did not take part in building the businesses that use the road or in the assembly and delivery of the products of the businesses, so you do not get to share in the reward of the profits at those businesses.
Now it's easy for people to listen to the jerk in the White House and if they don't think this through, they might buy into his notion that we all have a hand in each other's successes, therefore it should all be shared.
But that silly concept falls apart at the first step: motivation. If you are forced to share the profits of your effort with those who had no hand in your business directly, then why would you do it? If you had to dilute your reward for your work by giving it to those who had no part in directly assisting your work, would you feel inclined to start the work in the first place?
Each person should be rewarded for the value of their direct contribution - aka, labor. The guy who built the road - he didn't raise the money himself, take the risk of not getting paid for his efforts, or respond to market demands after the road was built. He was paid - by the hour - to lay road, and he was paid with money that was raised by taxing those who work at businesses. He did it voluntarily and thought it a fair deal.
That Obama sees the road builder as some sort of investor in the commerce of every business that uses the road goes to show that a university degree is no guarantee of intelligence - he has no understanding of commerce, business, labor, or pay. How do you get to be an adult that graduates from high school without that understanding?
Further, his argument isn't for equality. His argument is for greater taxation so that the government can control more of society. He doesn't respect the labor of either the road builder or the entrepreneur. If he did, he would honor those efforts by allowing them to keep their earned rewards. Obama and Elizabeth Warren want what isn't theirs, and that's theft, and theft is no honest labor.
Value is cumulative, and each person who contributes gets paid for their part in assisting that accumulation. But a one-time contribution does not make each person an investor in the entire enterprise. Only the person who risked creating the enterprise in the first place is due that. Roads are not a venture of risk, which is obvious to anyone who gives it any thought.