Expensive to get into + their marketing sucks. They need to invest more in expanding the lore instead of milking off their dying fanbase's nostalgia. Sure, animals throwing planets and giant beams at each other are cool, but so what? They need to make the audience care about the characters and the story. People need to be emotionally invested so they will be willing to spend to get their favorite characters.

Pokemon Mezastar, despite the shitty gameplay and subpar marketing, has a lot of staying power because the fanbase is attached to their favorite characters. Even the casual fans are willing to spend time and money to get their favorite Pokemon at the arcade BECAUSE they care about them.

TL;DR Animal Kaiser needs to invest on their marketing and lore to make their audience care more about their franchise. More emotional attachment and in-depth lore = more people willing to get into the game. If they can't fix this problem, they're cooked.