The Sensor Business
There was a time, when Fujifilm was making its own sensors.
However, at some point in time, Fujifilm sold its sensor business to Toshiba, which later on sold it to Sony.
As of today (and as far as I know) Fujifilm only makes the color filter array for sensors. Fujifilm also cooperates with Samsung on the ISOcell+ sensor development, which we reported about here.
In short: Sony dominates the sensor market, and most camera manufacturers buy all the sensors they need from Sony.
This gives Sony a huge advantage, as Fujifilm managers Toru Takahashi and Toshihisa Iida said back in 2016 here:
Sony has a big advantage, they make their own sensors. That is a very big advantage for them.
FujiRumors got information years ago, that Fujifilm had a contract with Sony, that allowed them to use the latest Sony sensor only 6 months after Sony used them on their own cameras, giving them a strategic time advantage (timing is crucial in business).
I don’t know if this contract has been changed in the meantime, but what I know is that Sony officially said once, that they will keep the best sensors for themselves, and not sell them to other camera manufacturers.