1) North American consumer are marketed to believe bigger must be better. It isn't just sailboats, SUVs and McMansions are prime examples
2) As the market for New Sailboats has shrunk from 110,000 units in the late 1970's to 5,000 units in 2010, boatbuilders have had to sell fewer; larger boats to defend their margins.
These 2 factors combine to make the under 30 ft market small. WD Schock builds a charming 25 footer, a perfect weekender suitable for 95% of people's true sailing - the Harbor 25. Yet, new boat buyers are looking to buy a 45 footer, that they will rarely sail because it is too big