I don't follow that stuff, but does Metabones make a Nikon F -> Sony E speed booster?
> Nikon made some of the great smaller-sensor size lenses that you can get for APS-C or micro 4/3rds.
They did make smaller lenses, but for the Nikon 1 system, which was an underrated system. I became a 4/3rds shooter when Nikon cancelled the Nikon 1 line, but I still use my J5 (which is what the first gen Nikon 1s should have been like). IIRC, adapted Nikon F mount lenses on Nikon 1 focus fairly quickly because of the on-sensor PDAF, but you're limited to center AF only.
This impacts both what choices you have, as well as what you can expect to pay for a given set/quality of glass.
To Wit: A Canon 10-18 is ONE THIRD the cost of the Sony E-mount 10-18. Yes, the Sony has a constant F4 aperture and the Canon doesn't. And yeah, on the other end Canon has the 11-24 f4 L, and yeah it's at least double the price of the Sony.
tl;dr - Sony's issue is you usually just have midrange options for everything, even if you really want a lower end lens that just hits the right range.
Also, you can just adapt lenses from Canon to Sony.
In volume, yes. In profit, it's still close, but mirrorless has been closing the gap for a long time.
And Sony used to be king of the hill with mirrorless, but Canon and Nikon have quickly caught up and the playing field is a bit more level (even as Sony holds the crown for most of the technical features).
The thing is, ecosystems matter a lot past the hobbyist stage and there are still a zillion more Canon and Nikon lenses floating around that people love and use.
That said, I now use both Sony (APS-C mirrorless) and Nikon (full frame DSLR), and like both for different things. But I wish I could have my Nikon lenses on my Sony (with no compromise), and wish Nikon made some of the great smaller-sensor size lenses that you can get for APS-C or micro 4/3rds.