Technically, MFT is pretty pointless.
Even if the advantage of APS-C to MFT was rather miniscule (which of course it isnt) - an APS-C sensor costs maybe $50, probably less, in production. Compared to the price of making a camera, thats already nothing. Thus using even smaller sensors saves nothing in respect to cost.
And having larger sensors makes lens design easier. The maximum aperture doesnt need to be made so high - at a certain barrier, it gets really complicated to offer even more aperture. Plus the demands in manufacturing precision of course raise with smaller sensors. So you dont save anything at all at that end with smaller sensors, either.
Low maximum aperture also means the maximum light per area isnt as high, which means the photographer doesnt have to stop down because he has hit maximum shutterspeed and still gets too much light in bright sunlight.
Lens size isnt much of a valid argument either. A Leica trinity 28mm f2.8, 50mm f2, 90mm f4 macro for full frame is still quite miniscule. A reasonable current Nikon trinity like AF-S 20mm f1.8, AF 35mm f2, Tokina 100mm f2.8 macro also isnt exactly killing you with their weight.
People who like a high quality 3x zoom trinity instead (something like Nikons 14-24mm, 24-70mm, 70-200mm at f2.8) might indeed complain about their weight, but they can get lightweight options from Fujifilm X etc. In fact Fujifilm already has one of the best convenience zooms - the 18-135mm - if thats your thing.
Sure you can have more demands for focal range and then sensors will have to get smaller. Like the Nikon P900 with what was its focal length range again ? I think something like 24-2000mm small format equivalent ? Quickly even MFT will be too large for such extreme cameras. But thats a special case.
So why does MFT still exist ? Well there are historical reasons - there was a time when even APS-C sensor have been really expensive. And currently they at least have at least one niche - old people who have problems to keep their camera stable. And MFT also benefits from simply being small and thus able to use certain new technologies first, such as backlit.
However, with the Nikon D850 even full frame is backlit now.
And the niche of people who cant hold their camera steady, if the rumor mill is to be believed, will soon be targeted by Fujifilm too, since they apparently also want to integrate sensor stabilization into their cameras. As long as you only use prime lenses and dont demand too extreme focal length - Fujifilm offers you plenty of small and great glas. And Fujifilm really aint that much heavier than MFT with usual lenses.
Thus personally I wouldnt be too surprised if MFT will be gone in 5-10 years.
I shot a dance pushing the ISO as high as 1250...it was pretty comparable to my D810 at 1600 and far far far superior to the 5DsR that I borrowed from Canon a few years back.
Nobody (sane) ever accused the Canon 5Ds of good high ISO performance. Thats a pure ISO 100 studio camera. The D810 isnt exactly the greatest high ISO camera either.
Whats the comparison with a true high ISO monster, like the Nikon D500 ? Heck, what is it to an average design, like the Nikon D7200 ?