Getting daddy involved seems to be the go-to for a lot of people regardless of their political leanings. Rather than being the thing of last resort, we tend to start with government involvement.I suspect that the reason people are so eager to justify spending other people's $30M for the bike paths in their own backyards, rather than trying to use private means, it's just way easier to have the government do it.
Little to no chance of failure. Virtually no chance funds will fall short. Virtually no chance the people who are against the idea can have any real say to stop it. No chance that land owners can opt out. It's about risk. If it's funded privately there's a fair chance it won't happen. Get uncle sugar agree to do it, it's a done deal but for the doing.