lol what? You literally have Minecraft, MLB, FIFA, Madden & NBA 2k in there
I'm not sure it can get more appealing to casuals.
Not even mentioning other top list games such as Destiny 2, Siege & Horizon 4
Whilst true, with the exception of MLB, those other sports titles come to Game Pass several months after their release, when they can already be picked up for really cheap. Most casuals who play those kinds of games on an annual basis, aren't really likely to wait 6-7 months before playing the latest FIFA or NBA 2K, because that's one of the few titles they purchase all year anyway, so it's not really a question of cost being the limiting factor.
Instead I think those sports games on Game Pass (with the exception of MLB as I believe that is releasing day and date) are instead likely to appeal predominantly to those who actually aren't that bothered about playing said games, and will basically just try them on Game Pass or EA Access because they're there.
Obviously EA know this too, which is why they put them on EA access so much later. They essentially sell the lion's share of copies in that first half or more of the year, and then throw them on the service when they know demand and value/cost is already dwindled.
Likewise, to the casuals who basically buy and only play games like COD (not even on GP) and FIFA all year, Game Pass actually makes less sense, as you're paying every month for that game and potentially up to £120 a year, when you could instead buy it for £15-£20 and be done with it, especially if you plan to play it all year anyway.
Game Pass instead appeals to core gamers, who basically want as much as possible to play, and don't necessarily care when or what they play, with the exception of Microsoft first party stuff which unlike third party titles, is always guaranteed day and date (unless it's PC only or PC first).
I also think we need to realise that first party games are also now tentpole casual titles. Games like Zelda, Super Mario, Smash Bros, Mario Kart, Animal Crossing, Spider-Man, God of War, Uncharted 4, The Last of Us Remastered, The Last of Us Part II, Horizon Zero Dawn etc, are essentially 20m+ selling franchises now, and as such actually sell similar to some of the biggest third party games out there when looking at platform specific sales. So I don't really know why people are discounting these exclusives and only concentrating on third party games.