I absolutely get what you are saying, and you aren't wrong.

To the OP, the point is don't skimp on a multi-million dollar career opportunity by wearing your dad's suit, or one that clearly doesn't fit, or is wrinkled, or...

No it doesn't have to be a blue suit, but also realize the vast, vast majority of applicants will be wearing a blue suit, with a white shirt, and maybe a little color other than a red tie. There absolutely have been people hired wearing grey suits, and even tan. But that is a super bold choice.