The "TrueCost" is never known until you stop boating. Only then can depreciation be factored in.
I know of a couple who bought a new boat, kept it in good order for twenty five years and virtually got their capital cost back. I also know of people who bought new, found the activity or boat did not fit the bill and lost tens of thousands in a short space of time.
Undina the Abbeking and Rasmussen, Rhodes design classic that Griff Rhys-Jones completely restored cost £75k, nearly £500k in restoration and yard expenses and when sold brought £75k!
I think most people over value their boats and like houses and Estate Agents Brokers overvalue to get boats on their books leading to some head shaking when it is finally time to swallow the anchor.