It's that marketing genius. Get 'em all horny about every model years significant improvements to keep 'em buying new boats. Drives used values down, but used boat sales isn't what keeps the doors at the factory open.
It's alot like the snowmobile market. Buy a new sled for a reasonable discount ride it a year or two...by then it's antique tech because of advancements, then try to unload it against alot of competition.