Just a comment.
Here in the US with the environmental regulations and permit requirements it seems that not many more boat moorings/ slips/ docks can be built (could be wrong on this). So what will happen. You have all these old boats taking up all the available dock space and new yacht builders wanting to sell new boats, but no place for owners to put them. I would think the same thing would be going on in Europe. Many boats it seems could last 100 years given some decent maintenance. So what gives? Seems a major hold up in selling new boats would be where is someone going to keep it. How is the mooring availability on the mainland us (here in hawaii about the only moorings available are at state harbors and they have a 5 year waiting list) and what is availability like in Europe?
BTW boat is a 1978 S&S 34, plan to keep her as long as I can sail her then give her to my kids (if they are interested). She should last as long as fiberglass hull lasts- say maybe 100 years. She is pretty simple to maintain as she is so basic.
Yes you are right in what regards to Europe and the situation seems similar to Hawaii. Long waiting lists on many countries and very expensive marinas. France and England have big problems. The costs are so high that if you have money for them you have also money to have a fairly recent boat, so old boats has you say will start to be a problem since nobody will want them.
Typically for a 40ft boat you pay on insurance and marina about $8500 a year, not counting with maintenance that will cost about $3000 if the boat has less than 5 years and more if it is older.
Disposal of fiberglass boats is complicated, costly and raises ecological problems. I bet that soon we will have to pay for each boat a tax equivalent to the cost of its disposal.