(With regard to Lasers and knock-off sails) Maybe not close it officially but can be made redudant were the official sails to get to a reasonable price/longevity. The only argument for the knock-offs seems to be that they are cheaper and thus enable more people to join in. Were they to be the same price (per year - hence longevity) there would be no cost justification and thus no reason for a club to not follow class rules.
They do have a way to go though as my Intensity replica (which you can pick up for around £150 in the UK) is just over 18 months old and still looks pretty new and is the 'correct' shape (and it has been hammered believe me).
My 'genuine' sail which came with the boat and had only been used 3 or 4 times looks in much worse shape.