I share your thoughts on this topic. My 6 is my third cycle to wear a car tire! Like you, I've accumulated over 80K miles on the Dark Side but have never used a run-flat or snow tire. Summer thread tires with adequate "rain grooves and siping" have provided great performance and longevity, something I could never get from a Cycle Tire. My first attempt at Dark Siding was my Yamaha Stratoliner S with a Good Year Triple Thread. That tire provided acceptable performance but felt like a "cinder block" on the rear. Never did wear out the tire as I traded that bike for a Yamaha Royal Star Tour Deluxe which was quickly fitted with a Federal Summer Tire and handled so well I mounted a identical Federal after the first wore out! My 6 has been fitted with a General G-Max from almost day one of ownership. Removed the stock tire after 1100 miles and have never looked back. I'm about to install my third Max as the second Max is ready for replacement. For me, the greatest pleasure of Dark Siding is having a large array of tire thread patterns available in either standard radials or run-flats, should I choose that route.
From what I've read and digested, the move to "winter tires" was the result of a "more motorcycle tire like feeling" provided by the "stiffer run-flat side walls". That said I'll be the first to admit that single ply sidewall radial summer tires can produce some "squirm" but that is usually remedied with the "right and higher pressure" for achieving a "sweet spot"! Im my case that's usually 43PSI in the Max.
Ride Safe
bob109