Impressive camera for sure but something missing in a couple articles I've seen on this is glossing over the fact that Nikon/Canon have a huge library of lenses.

With photography it's largely the lens that drives the photo(which makes sense when you think of photographing in terms of painting with light). Until you see Sony breaking out the 300mm F2.8, 400mm F2.8, 600mm F4 and others you won't see much pick-up on the segment they're targeting(1DX, etc). For instance a 400mm F2.8 goes for 2x the cost of this camera alone(~$10k).

There's adapters for EF->Sony, however they're hit and miss on functionality and focusing speed.