I am not sure any of the major paint companies make a bad product anymore. Any quality body shop will give a 5 - 10 year warranty on paint. They have to because next guy down the street will if they don't and the warranty is based on paint company and there products. Paint is like anything else in the world, occassionally a bad batch is made but overall all the quality urethanes/water borne base clear systems are excellent and will hold up almost indefinitely if properly maintained.
Harley, just like GM or BMW takes bids on products, BUT if that product has a warranty problem you know who handles the warranty? The supplier in the end just gets a bill so they have to supply good stuff as a bad run or cheap product will be warrantied by GM or HD and then the supplier get the bill in the form of straight dollar deduction from the contract price for the next paint order and no company can afford many of those happening when they already are selling at the bone.