That is because there is no "proprietary" gelcoat. IP does not, and never has, manufactured gelcoat. The companies that make gelcoat may make a "proprietary" color, but not a base gel coat. IP may use higher quality gelcoat than some (I don't know), but it certainly isn't unique to them.
I beg to disagree. Island Packet at one time acquired a very innovative company that pioneered vinylester resin usage in boat manufacturing, - Arjay Industries. This is where fiberglass components and technique currently used by Island Packet came from as per Bob Johnson (Good]Good Old Boat - Welcome to Good Old Boat Magazine
Old Boat - Oct. 2004 Island Packet Interview):
"...the same firm that worked for Hutchins, Arjay Industries, did glass work for us. I wound up buying the assets of that company, it was right across the street, and I brought it all over, people, equipment, everything . . . and he got out of the lamination business. Our glasswork was overdue to be brought in-house, from the standpoint of the type of control we wanted to exercise over it. Bob Cottrell, owner of Arjay Industries, was not your basic glass business owner, he was a Harvard MBA and a chemical engineer, and he took a very methodical approach to fiberglass construction. One of the things he developed was a spray core decking material that eliminates foam or balsa or plywood. You get the Oreo cookie concept of glass, lightweight filler and more glass. We won't use it on the hull because it reduces puncture and impact resistance, but it makes for a very stiff, lightweight deck. On the hull we use fiberglass, one laminate after another. We bought that technology also and brought it over as well. So we have a 10-year warranty on our deck against rot or delamination. No one else can do that, balsa and plywood core decks will eventually deteriorate. Some other companies do spray core also, but I don't know who they are; but there is a company out there that sells a similar process (ours is a home-built process, internally developed). If you buy a 15-year old Island Packet, you will not have that core material rot. It can't. It's microspheres in resin. It will be just as good as the glass around it."
Next time you walk around in a marina, - do yourself a favor. Find any 20 years old chlorox bottle boat and compare gelcoat condition to a 20 years old Island Packet. Then draw a conclusion...