I don't see Sony combining everything they have into one big monolithic subscription service. It could end up being something meant to appeal to everyone that ends up appealing to nobody because it has to be quite high in price. At some point in makes sense to limit the offering of a combined service in favour of having a variety of smaller more targeted subscription services.
Maybe have something similar to what NowTV do in the UK where they have a sports pass, entertainment pass, movie pass and kids pass. Each one is a separate sub...
Sony could have Entertainment Pass, Anime Pass and Gaming Pass (not to be confused with GamePass!
) and Music pass. A clever thing to do to increase adoption of multi-subs would be to include a little bit of each in the other passes so, if you have the Entertaiment pass you might get to play some older games that are part of a series but if you want to play the sequels you need the gaming pass. And similarly on the Gaming pass you could have access to the first season or first few episodes of a series that encourages you to get the Entertainment pass as well to carry on watching. Sony have a ridiculous amount of media that they could really exploit if they execute the plan well and should have really established themselves already as a top tier service provider instead of sitting on their hands while the likes of Netflix, Amazon, Microsoft and Disney have been steadily growing.