Not sure about you, but "many BMW riders" seem to be in their ... ah ... later years. They don't want to give up riding, some (on this forum) have jumped down from the fabulously equipped LT's to the lighter, sporty RT's (or GS's), and some are considering their age and mortality, and thinking a few hundred pounds lighter than an RT, might be wiser for their riding future. That may explain some of the references you cite regarding comments about the new(er) RT's weight.
My guess is that BMW's primary riding audience in Europe is significantly younger than the average BMW rider in the USA. The young one's are looking for fast and sleek and "modern", and don't much care what that requires technically. I don't know for certain, my reference to BMW owner's average age largely anecdotal. I agree with you that if BMW is your favorite cookie, and the weight LT or RTs are becoming a bit much for you, dropping down into the F series bikes might be in order. As far as BMW is concerned, their bikes are made to fit "marketing slots". I wouldn't expect them to change the RT's basic market slot, however they decide redesign the next one. If they make their RT's light and snappy, maybe like an electric Moped, they could lose their primary audience/market overnight. (Of course, apparently that's not stopping them from moving to a reported, "all EV" bike line in the near future. Maybe they're just like the American car makers who were bamboozled into making electric "muscle cars" and trucks, which are contradictions in terms and purpose, which from sales figures, apparently have NO market at all. But, of course, I digressed a bit ... 😁).
As far as I'm concerned, (a) I'm not riding enough to justify owning ANY bike, to my better half, (b) I "feel" that I should be on a GS, because the majority of my years of riding have been off-road (but that may be a close thing, maybe street and dirt are split evenly), but my body says "Idiot, you ain't 20 years old anymore!", and (c) Over my 20 years of owning BMW motorcycles, BMW has almost deliberately made policy changes that put me off their product. A half dozen years ago, BMW's were the only motorcycle I though about owning (even though all my dirt bikes had been Japanese). That attitude has changed almost completely. It's not so much that they discontinued sales of BMW specific tools and their maintenance DVD's, which ticks me off to no end, but the German's at BMW are flat out arrogant about the value of their product, and express an utter disregard for their customers. It's as if, they consider their customer base as suckers, who will accept any crap that they choose to put on the plate. I'm sure that I have a distinct minority opinion, but hey, I'm an old and crotchety guy, and I don't really give a f**k anymore for decorum or dissembling.
So, my next bike will probably be both lighter, and "OTB", as in "other than a BMW". They can build their next RT into a 3000 lb battleship, for all I care. (I mean, they're gonna do it anyways, regardless of what their owners feedback is. Oh, wait a minute, maybe I'm wrong. They did eventually respond to owners complaints about the drive shaft issues. It only took them 20 years to do so, while owners picked up the tag for their engineering and manufacturing mistakes.).