@Film-Niko you can't be denying the obvious trend of increase in the element count, weight and bulk of photo lenses that's been going on for 10+ years. IMO this is due to the combination of digital resolution increasing and pixel peepers willing to spend money on a regular basis to examine every single skin pore on their wives' noses at f/1.4. So many people would have been happier with a $250 microscope than with a $5K mirrorless photo kit and don't realize it because microscope makers do not have marketing budgets.
But not all lens mounts are affected at the same rate. IMO this is about volumes / economics. More popular mounts got infested first.
The M-mount is just behind due to the slower pace of product refresh. Leica hasn't touched some of their Summicrons for decades. Zeiss hasn't updated their M-mount lineup for many years, but eventually they will release the ZM versions of their Otus monstrosities. But Voigtlander happily offers comically huge and heavy lenses that, in my humble opinion, defeat the purpose of owning an M-sized rangefinder. And god helps us if Sigma ever decides to enter the M-mount market. Expect plenty of ART.
The optical design limitation of SLRs that have to clear the mirror box does not apply to mirrorless cameras, so whatever is happening to mirrorless optics will happen to rangefinders as well. Just give it time.