They are actually indie developers. Sure, Pokemon is the biggest franchise in the world. But they don't have anything else. Town Hero was a massive flop of scandalous proportions like we have never seen before. They also only get one third of the Pokemon profits at most. That's about 50 million dollars of profit every year. Compare that to Bandai Namco that made Snap, they make 2 billion profit every year. Or another studio, a single game like Death Stranding cost 200 million in production.