What’s the story behind Great Fountain and Silver Fountain fast food?

So I’ve always wondered about Great Fountain and Silver Fountain in the food court.

They seem so similar. The food tastes almost the same, the menus overlap a lot, and they are right next to each other. But they are competitors. From what I notice:
• Great Fountain usually attracts way more customers
• Silver Fountain still gets business, but less. Unless Great Fountain is closed, then people line up at Silver

It made me wonder… were they once the same restaurant and then split up to open their own spots?

Anyone have the tea on these two? 😆😆