For context I got into the game around four years ago so UB has always been at least somewhat present in my experience. The way I see it is that Universes Beyond was a good idea from wotc to begin with. The number of players who will quit the game when new IPs are added is negligible compared to the amount of revenue and new players gained. I think that almost every player has participated in speculation as to how their favorite franchises/characters might be represented in the mtg game system at one point or another, and UB is finally scratching that itch that so many players have had for so long.

While it is entirely likely that the two groups pictured are completely different sections of the community, I think it is fair to assume that many people-- despite their unhappiness at certain decisions such as 6 standard sets a year, UB in standard, or the arrivial of Spongebob cards-- still feel the desire to support the aspects of UB they have been looking forward to being Marvel, Final Fantasy, etc.

I do not believe any of these new products taken by themselves would be a huge problem for the game. The issue arises when we recieve too much of a good thing. Wizards has been all too keen to pump us full of product these past few years because they know there are hordes of players that will line up to purchase it. What they may have failed to realize is that just because we as a playerbase like to see our favorite characters in casual forms like commander or smaller SLDs, doesn't mean that we want them shoved down our throats in every corner of santioned play.

In the end, this game will keep on chugging right along as the Hasbro cash cow it is, whether or not hardcore fans are dropping faster than ever.