I believe it comes down to economics 101. at least in my neck of the would it comes down to how much they can make on you during the season, If you rent a slip, store and service your boat with the marina then you are golden, if not you go down into the B pool of clients gas, beer and toys.

I get my storage and service at the dealer i purchased from, plus a couple extra toys and marine parts, the rest i spread around.

FWIW I like my dealer and they are 60 miles away, also like the supra dealer 20 miles away, but they no longer sell the brand.

Not so sure the like me on the BB... LOL