As we get more populated prices just go up. Also the easier it is to live aboard the more will do it, hence more demand---less supply. Marina's are like any other buisness they need to make money... and no one ever promised me a living. I recently purchased a mooring, because docking in povincetown is prohibative in the summer. I would suggest if you insist on living in the continental US that you invest in a good water maker / wind generator and better dinghy and get used to mooring living.
Or you can get some buddies together and purchase some land on an inlet and start a small marina co-op.
However my personal solution is to stick to the mooring and eventually sail off into the sunset for cheaper pastures. Ok well more like sail south / south west to caribbean and south america. Also I never see myself retiring either will always do something that generates some sort of income.
Tranquility 'Columbia 29, 1965'