A micro four thirds camera is objectively inferior to film, because it doesn't have the same visual/perceptual resolution. That said, IBIS and high dynamic range sensors are amazing technology that we're all thankful for. Also, you can handhold 600mm lenses on full frame cameras also, Nikon for instance has telephoto primes that use phresnel lens elements and are definitely handholdable. I shoot the 600mm f/6.3, 500mm PF f/5.6, 400mm f/4.5, and 300mm PF f/4 all handheld, and while the 600 is on the tail end of what is handholdable and you give up some light for reducing the size/weight (mostly through a smaller objective), it's entirely doable. So your example would have been better looking at full frame mirrorless. Sure, m4/3 lenses are significantly lighter/smaller, but they're also not remotely comparable to film.