As the recently-indoctrinated umapilled person in the room, I say no. Bronies were freaks in that they sexualized and made a fuckton of creepypastas of colorful cartoon horses for a show clearly aimed and marketed towards kids. They traumatized a shitton of kids and some even complained years later that it desensitized them to fictional porn and horror. I find that disgusting in its own right because I really think that shit should have been kept far away from growing kids, but you even had weird shit blow up on YouTube that was just meant to scar everyone who saw the "parody cartoons." Can't remember the title but I just remember some weird shit with Applecrack or whatever her name is.
The main difference between MLP and Umamusume is that one is supposed to resemble actual horses and the other is anime catgirls that are just horses instead. One is weird to fap to unless you're a furry degen, the other is more acceptable since they are human except for the ears and tail. Not to mention, there is rumors that the Cygames yakuza will come for you if you lewd the horses, but that doesn't stop people. It also hasn't stopped people when the game was Japan-only before us global people even got access to it, so clearly no one cares but it is kept more hush-hush than what bronies were doing. Feels like a speakeasy if you want "the goods" of Umamusume porn.
The only annoying thing I can see happening for years to come is the yuritards versus the Trainers because the yuri carpet munchers claim the entire game is for lesbians, when clearly there is some directed fanservice for the player. They don't call Super Creak "Super Freak" for no reason. Oh, that and you will see Umamusume pop up randomly probably, but I doubt it will ever go more mainstream. I sort of expect the game to lose players soon because the honeymoon phase is going to wear out at some point and people leave because the grind isn't for them. It is also clear most of the players resemble Hoyoslop fans since this is apparently most peoples second gacha with how many dumbasses point out the pity system and how it differs from Genshit Impact. I guarantee those dumb fucks will leave first and go back to suckling Hoyotits.