The way I see it, you save money by not paying for a service which you assess offers no/little value. This is the same for every subscription service including Netflix. You have no control over what appears in them, when it appears or how long it'll remain in. I was a long-time subscriber to PlayStation Plus but quite when I felt I wasn't getting sufficient value.
This. If you know what you want you'll never have a problem. I can see GamePass is insanely good value for some but not for me. I have so little playtime that when I do store it up for special occasions, I want to play something specific. As I said before, if I was 20-30 years younger GamePass would be right up my alley. It's great for people with more time than money and people who are less fussed what they play, they just want a big choice of fun stuff.
I see the value calculation for GamePass to be if you get one AAA game every 6 months that you play via GamePass you break even and anything beyond that is a win in $$$ spent. Given that I did the 3 years of pre-paid Live to 3 Years of pre-paid GamePass Ultimate conversion the value ratio is even more absurd than that for me since I paid $181 for it. That's one full-priced game played a year on GamePass for either Xbox or PC and I break even in $$$ spent.