I think what Remediation mentioned above is a big part of putting these costs in perspective.
Reupholster and getting new covers made, etc…are expensive. However, if you hire quality people for those jobs, the work comes back looking as good as new.
And the difference in price between reupholster costs (which look high at first) and then simply getting a new boat (whoa!) is so huge - especially these days.
I think a good boat reupholstory business should be able to get you taken care of on your year boat with the older style marine vinyl and get make it all look new. It will be pricey up front, but if you take care of it properly and keep it covered, should last 10-15 years pretty easily.