The article did not say that Sony would stop selling sensors to other camera manufacturers. It did say that they would not sell their latest most innovative sensors which is effectively what they have been doing anyway as two years later there is still no other 42 megapixel 35mm format camera on the market.
The statement from the interview, I believe, was in the context of 35mm and APS-C, and maybe even 1" sensors and should not be interpreted as meaning that Phase One and Hasselblad would no longer have access to the latest 645 format sensors. Now if Sony were to come out with a 645 camera like that, maybe they would hold back until they were established in the market but it's highly unlikely that they will build a camera like that and also highly unlikely that they would exit sensor sales to that market.
As for 44x33, I guess it is slightly more likely that Sony would get into that camera business with a higher megapixel 44x33 camera which could affect the upgrade cycle of the current 50mp 44x33 sensor camera manufacturers (but i doubt it)
I think effectively, if true, it means that a Sony a7R Mk x will always be a generation ahead of a Nikon D8xx from a sensor perspective, which it already has been for the last two years. So, in my opinion, all of this Internet furor over this with every forum blowing up about it, is much ado about nothing.