Why should they try to improve, reading all the bikes you owned, sounds as if you have more money than common sense, if you keep buying them they wont try to improve much.
Myself i've owned 2 harleys, an old evo, and my 2007 se ultra. The evo never gave me trouble, the 2007, thats another story, and there will not be a 3rd harley in my life.
Do the math, I average 25K a year on a bike, and my wife closer to 30K. Other than her Heritage which in just under 3 years had just over 80K and trade was not enough for us to let it go we trade every two years, bike under 50K. Funny story on her Heritage, the stator went out, two miles from the dealer. 21 month old bike, 53K on it. New Service writer looks at the bike writes down mileage and tell me its around 500 for the new stator and labor. I said nope, under factory warranty. He said I ride the hell out of the bike, I said nope rode it once its my wife's.
Cost me 5K to go from her 13 Street glide to a 15 Road Glide special. I figure 2500 a year is not bad. Over 25K miles a year.
Usually costs me 6500 to get a new CVO every other year.
07 was first year of the 110, way high number of issues.
A friend tried to trade a 5 year old bike with 110,000 miles on it, they told him to keep it, and they would take 1K off a new bike.
Again why I trade before 50K, unless I plan to keep the bike until I can no longer ride. Makes economic sense to me. This also means the bikes are traded when the warranty is up, so I do not buy extended ones. My wife and I both love to ride. This is our bond and something we both love. My 06 truck just hit 60K three weeks ago. I have traded 5 of my bikes with over 45K on each in that amount of time.