Because there's no perfect solution. If a piece of land has that much utility the government could take ownership (possible compensate the owner) and be respons

Because there's no perfect solution. If a piece of land has that much utility the government could take ownership (possible compensate the owner) and be responsible for maintaining and upkeep. I mean your example in the UK, I can't believe every landowner that has a public right of way on their property is thrilled about it, especially in cases when they went to do something with their property and the government told them no because of the right of way. What good is owning that property one might wonder? If it's that important to everyone why not have the government purchase it and maintain it? Every landowner might have a different opinion of what the best solution is. Good luck writing a law that appeases them all.