In order to own the 300K+++ boats, I think the most important factor here is to own your own business, and work hard building it. Working for someone else (corporations, etc.) will most likely go nowhere fast. This I know firsthand. If working for someone is a must, then the Medical, Legal, or Computer industries are probably the best bets, none of which, unfortunately, I'm in. Looking at your profile, at least you were smart enough to enter one of these career choices.
Also, reading what you currently have, be extremely happy with it, some people have much less and aren't going to get anything anytime soon. Most of the people I've seen who have the large Cigs, etc. are in their 50's and self-employed, meaning that once you get to be around that age, you'll probably be able to buy one as well, just give it time to build equity and, of course, an excellent credit rating .
I do agree that New-Used is the best way to go, what with the outrageous prices of new boats.
I'd love to have a boat now, but it's impossible. I'm recently married with a house payment, 2 car payments, and the sheisters who sold us all the wedding services really ripped us (as I thought - since the bride has to have everything right ). Once these (cars, wedding) are paid then who knows, there probably will be something else to pay. I just need the guts to go into business for myself...