To be honest, I don't think a whole system of designated bike lanes on every road will ever be practical or gain either popular support or dollars, at least in our lifetimes.
But I did have thoughts regarding what might be called "reserved when present" bicycle space. Wherever there is a right lane, half of it is painted to indicate that it's reserved for cyclists when cyclists are present. All other times, vehicles can use them as regular lanes.
If nothing else, this would send a legal and visual message to drivers that cyclists have the right to the road, and would provide a visual guideline for passing space.
It wouldn't require the same restructuring of our roads that designated bicyle lanes would require. All it would require is a lot of paint, probably a different color than yellow or white. Of course, there will still be issues and obstacles, such as 2 lane highways, rules for intersections, etc., but I think something resembling it might be a practical compromise.
And of course if new roads are built, perhaps they should have designated space for bike lanes to facilitate flow of traffic.
If there is already information out there on this approach, I would appreciate links. Otherwise, I hope for a heated discussion and/or brainstorming session.