It's not the responsability of Customers to make sure what Sony's chosen contractual relationships elsewhere are - Sony can engage in whatever contractual relationships it wants in whichever way it wants (and thus maximize their profits), but if it breaks their side of contract it has to pay the penalties for it, quite independently of why.

This is how Contract Law is designed exactly because otherwised it would make it impossible to Trade: if a purchaser had to track all contractual relationships of each supplier, then as those too were linked to the contracts of their own suppliers, of the supplier of the supplier and so on. So Contract Law neatly isolates each Contract relationship from all the rest and legal responsability starts and stops at that Contract (including the implied Contract in a Retail Sale) and only betwee the parties of that Contract unless very explicitly stated otherwise in the Contract.

So, have customers in this case entered into a Contractual Relationship where Sony gets to pull the plug whenever it feels like for any reason (which are probably invalid contractual conditions for retails customers in plenty of countries, though probably not the US which has near-zero consumer protections) in which case the problem is of the customers, or have they not in which case Sony is the one with the responsability (probably of refunding their customers) and it's up to Sony to exercise whatever contract clauses they had with WB and claim compensation from them for their own breach of contract, if Sony had such clauses in their contract (if not, it was their own choice, so tough luck)?