That makes sense and is how it's typically done up here. I read the GGP's post as a complaint against the developers not against the city/country/AHJ, who is the only one in a position to make the change (granting public right of way, or taking property via eminent domain as needed).

It was meant as a complaint against the county. They have a silly rule in place - developer must build sidewalks. That's it. No coordination between developers/land-owners. No plan to link developments. See the sibling comment about Loudoun Station - a large mixed-use development that isn't linked to the largest bike trail in northern VA.