André Langevin wrote:
....
Since
it will take me some years to get to this next boat, suppose i'm 50 years
old and i finally have that big 43-45 feet sailboat. What are the chances
i could use it for 15-20 years ? Could it be my last boat or will my last
boat invariably be a powerboat ?

This is an exceptionally silly question. You might just as well ask
if your next wife will best your last or will your last wife be a blond.

Frankly, I'm thinking my current boat will be my largest, because it
big enough to live aboard or travel where ever I want to go. However,
I'm expecting that at some point I'll want a smaller boat, perhaps two
- one sail, one power.