In addition to buck 460 comments.
Land owners are able to micro manage the 80 acre parcel they own. Think about that a bit, every 80 acres privately owned, has a person or persons who are able to work that land and keep track of every deer. They are not filling out land use studies, they are not petitioning there superiors for funding, they spend little time picking up litter, trail maintenance is nil.
Also don't forget, the two do not share the same goal, similar yes but not the same. Equal access for all? no. Small game, upland birds, waterfowl, songbirds, wildflowers, prairie restoration, and adequate numbers of all of the former to justify taxpayer expense.
I worked at two different parks. One was a State Park the other was a County Park. The budgets were very different the goals were fairly different. The state had less money to spend per visitor, but had exponentially more visitors. They had to provide lots of people an outdoor experience, and stay open 24 hours a day. The county had more land, and relatively few visitors, but the same staffing as the State Park. The county picked up cigarette butts, the state picked up beer bottles. The county would take the end loader back into the woods to help you extract a deer, the state would not even allow you to use screw in steps for deer stands. the county WANTED a park, the state had to have a park. All that above to say it can be done if the people want it bad enough to pay for it.