I see the weight claim often from people who have changed or consider changing, as well as in marketing of mirrorless cameras. However, many will deny it when confronted with the facts, either the facts or the reason for changing. The only roads to lighter gear are smaller sensors and/or smaller apertures. Mirrorless does have an advantage when using smaller sensors though; the fact that the size of the viewfinder is independent of the sensor size.I don't know the source of this generalisation but these points are the least important for me. I did change part of my kit to mirrorless for the short flange distance allowing to adapt many different lenses and the possibility of a magnified view through the viewfinder. The reduced weight/size is only a benefit if you choose the right bodies and lenses (as your table shows) :lecture:
The adapted lens thing is only valid for a small group of enthusiasts. Most people use native lenses for the system they've bought into. Most don't even know that they can adapt lenses, lenses with full functionality, like F-mount lenses on Nikon mirrorless included. I've had that discussion wiyth converts a few times lately.
There is of course a size advantage with mirrorless, since the shape of the camera isn't dictated by the mirror box, and I understand that many like the "always bright" viewfinder. Me? My liking for the original way of looking through a viewfinder, using optics rather than electronics, is gaining strength though. I don't care if the EVFs will probably be as good as OVFs in 5 years or 10 years or 20. If they are, fine, but in the meantime, I'll enjoy mirrors and lenses and cameras that say click clack.