Well that's not an indicator of an established relationship really. All these companies sell shows to each other when they don't want the show for themselves or someone is paying more. Abbott Elementary is made by WB for Disney. Disney makes Central Park for Apple. Sony makes The Boys for Amazon. WB made The Sandman for Netflix. The list can keep going on.

The big reason that Apple would acquire WB for is their library. Being one of the big five Hollywood corporations, they have so much IP and library depth that Apple can exploit for their streaming service.

It's good for WB because it'll be very easy for Apple to get rid of all debt that WB has built over the years. Or maybe Apple can keep WB and spin off all the debt along with Discovery into a different company and keep WB for themselves.