yeah. as shows like Stranger Things prove, quality exclusive content sells. Which is why MS/Xbox needs a strong lineup of quality exclusive franchises.
Theoretically, if Gamepass really takes off, MS could just go the way of Netflix and become platform neutral, meaning Gamepass is on other consoles and devices. That's my fear, and I hope it doesn't turn out that way, because Xbox still has a hardware history associated with it.
Or, they could use the success of Gamepass to sell Xbox consoles by making Gamepass an exclusive Xbox feature. If you want to enjoy all the benefits and exclusive content first, you need Gamepass - only on Xbox. That's what they need to market.