A small number of mobile games sell better make obscene money, the vast majority make a pittance or lose money. But corporate types cant stop salivating at the thought of being the ones to own the next candy crush, so they'd rather take a shot at that than produce something with merit that will likely make a reasonable return.
It was tricky to find actual numbers so correct me if I am wrong, but if you look at the entire lifetime net profit (not revenue) of Elden Ring since it's launch, it appears that Dragon Ball Bokken made all of Elden Ring's profit in just 2024 alone.
When you read Bandai's financial reports they always open with their mobile games, with From Software titles getting an "honorable mention" at the end.
I would argue the storyline was a big part of it. While barebones by today's standards, compared to the likes of Doom, Quake or even Unreal, it was pretty amazing to have a continuous narrative throughout the game.