I don't think you understand what Prestige means. It's not about ratings or spectacle, but farming industry awards to insinuate a premium brand.

Should point out as a sidenote, that Showtime's boxing promotions bring in pretty big numbers, often measuring in the hundreds of millions of dollars in PPV buys. (The record was $410 million for Mayweather vs Pacquiao that was a joint promotion with HBO and Showtime).

Now, all that being said they've obviously not reached the same levels of prestige as something like HBO, but that's irrelevant. Regardless of how well they perform, the entire point of showtime is that it's CBS's Premium network and longtime competitor to HBO.

Prestige is usually associated with awards…. And of all the shows you listed, Yellowjackets is the one with nominations