My neighbor in the marina has a 28' Bayliner with an I/O. He put one in because his outdrive was collecting too much hard fouling. He hauled it a month ago and spent 3 gallons of Muriatic cleaning his drive and that was with monthly bottom service. One might say his service was bad but I use the same folks and they do me well. One possibility is outdrives are rare here and the divers maybe didn't know how to deal with them. When I checked into one I was told I would need two for our 44' and that was too much cost for the benefit.