Most of the local access issues that I've seen are managed by local governments, maybe the state for the bigger beaches. We've had good luck over the years, but I am aware of one site in Newport that was shut down by a single "taxpayer" at a meeting.
US Sailing won't be sending lawyers to these meetings, so I'm not sure what else they can do.
Like it or not, there is more bang for their buck by supporting yacht clubs and community boating centers, who tend to have fixed venues and assets. This is where they seem to put the effort to increase access to sailing.
Maybe we need a sea change on our side; rather than pushing against the tide and burning out more people, work with the YCs and CBCs to get new access. We need to stop being so unrealistically cheap, as the days of truly free access are certainly gone and not coming back.
