So does Fuji. Fuji has a pretty unique sensor with x-trans.
Sony and Samsung are both producing a lot of sensors for mobile devices though. For example Apple has used a lot of Sony sensors over time. And likewise most camera manufacturers do not design their own sensors at this point.
Even if Fuji designs them, from a total dollar and cents sort of way, the better Fuji's sensors are received in the market and the more they sell, the more money Sony makes.
(and once Sony makes the money, it uses the same profits from Fuji to compete against Fuji.)
It's a sort of reverse competition, where by Sony is guaranteed victory simply because they participate in their competitor's victories.
Sony and Samsung are both producing a lot of sensors for mobile devices though. For example Apple has used a lot of Sony sensors over time. And likewise most camera manufacturers do not design their own sensors at this point.