Upload & Sell: On
It doesn't really matter if people, who need this kind of camera, would switch to Sony or not, but most of them will hesitate to invest into high end CanNikon gear from now on, IMO.
They will rather just wait how those two will answer to this serious challenge, and if that doesn't make CanNikon to wake up, they will most likely turn their heads towards Sony,
especially, if Sony brings some long glass to the market soon enough.
I do feel many are equally awaiting for Sony's lenses. The A9 looks great on specs but without the gammut of lenses most photographers will wait awhile. There are some excellent lenses available such as the FE 35/1.4, FE 50/1.4 and GM 85/1.4 but there are many gaps.
In contrast Fuji with the GFX detailed very carefully their lenses and how to present the GFX as as integrated system. Same as for the APS-C series with the introduction for the XP2/XT2/XT20 with the XF series of lenses are all excellent. If it were not for the lenses, I would not have even looked at Fuji.