Can't really agree with you since PS gives several of those things for free (currency, avatars, etc) for same or similar games and even more for PS+ members. But well perhaps the market see it like that and is happy =]
You can't agree with what? That adding V-bucks for Fortnite (and whatever the in-game currency for Rocket League is called) to the Series S is going to be more appealing to at least some people than a Seres S without those things?
Game Pass subscribers also sometimes get perks along those lines too.
Amounts of in-game currency provided through perks are generally very small, especially when tied to free services.
At any rate, Fortnite is an enormously popular game (Rocket League perhaps somewhat less so, but also has its fans). These games rake in obscene amounts of money from people purchasing their in-game currency. Clearly fans aren't getting anywhere near enough in "free" perks in these games, and are buying lots more. That strongly suggests that currency has a lot of value in the overall marketplace and will be seen by players of those games as a significant value-add.