Once you are up to long telephoto lengths, you have to have the same size lens for FF, APS-C and micro 4/3. You can't make a dedicated telephoto lens for the R7, M4/3 etc because at the long focal lengths the image circle is large enough for FF, and you can't miniaturise it for the smaller sensors. For example, the dedicated Zuiko Digital ED 150-400mm f4.5 TC1.25x IS PRO for OM Systems micro 4/3 weighs 1.875 kg, much heavier than the RF 100-500mm, and costs 2-3x more. Similarly, the Zuiko Digital ED 100-400mm f5-6.3 IS II lens is much heavier and more expensive than the RF 100-400mm. The RF 100-500mm is very sharp at 500mm, by the way, and the Zuiko at 500mm with its TC switched in is f/7.9, narrower than the RF 100-500mm's f/7.1. (The RF 100-500mm is f/6.3 at 400mm and so on FF and APS-C covers a wider range than the dedicated M4/3 lens.)