I looked up CIPA (Camera & Imaging Products Association) data on mirrorless cameras and made a selection of them. Being tested by an independent body, they should be much relative to one another if not absolute in real-world use.
Fujifilm XA3 - 410Fujifilm X100F - 390Fujifilm XT-20 - 340Sony Alpha a6500 - 350Sony Alpha a7R II -290Canon EOS M10 - 255Nikon 1 J5 - 250Olympus PEN E-PL8 - 350Panasonic Lumix DC-GH5 - 410As long as camera makers concentrate on compactness and light-weight, the situation will continue. Battery grips are somewhat of a solution, but large bodies and heavy batteries are pretty much dictated to get dSLR performance.
Thanks, Larry, that's really interesting!