Honestly, I know it's technically accurate to call various games "indie games" but it feels viscerally wrong to describe highly successful and famous game as indies. I don't think you can convince me (on an emotional level) that the statement "Terraria is an indie game" is not in some way inaccurate, despite it being constantly said.
Like, if you want to make an argument where the only requirements for being an indie game is that you self-publish, you could make the argument that a huge chunk of video games are indies because they are made in house and published in house. But I don't think ANYONE will ever call GTA V an indie game simply because it was made by Rockstar and published by Rockstar.
I feel like for an indie to actually be an indie in the modern day and age, it actually has to be somewhat small, otherwise you're just a regular ass video game company. When you sell millions of copies, have dedicated PR managers, a lawyer or two on retainer, how can anyone argue that you are an indie studio?