couple of different reasons in my opinion, 1st is where they boat. The guy I bought my boat from only used it in Lake Tahoe and he told me it just didnt get baking hot (unlike Needles and Havasu) 2nd is the Tower, alot of people either add a tower after they get the boat or upgrade to a different tower and then their old bimini doesnt fit. Also cost is a factor, after I bought my boat the 1st thing I did was order a custom bimini to fit with and on my swoop tower from Towerbiminis.com and let me tell you its not cheap if you do it right. That said though I could not live without it.