If anyone was truly as "equally talented" as John Carmack, they wouldn't remain unknown for very long. Plus, you can be extremely successful without having to be a celebrity, and John was always going to be successful.
Sure they would. They may be known but known to a niche group of people which may limit their success. Carmack is a self proclaimed hermit but he's been in the public eye for decades (through conventions, speeches, etc) and willingly pushes back against corporate bureaucracies (against Jobs, Zuckerberg, Gates, etc). That type of public persona adds a lot of clout and opens many more doors, genius or not. A genius hermit who doesn't rock the boat or is fine with the status quo might have a different path.
Well, the OP asked "what’s the trick to becoming a celebrity", so the candidate would be someone as talented as Carmack that WANTED to get noticed. It wouldn't take a lot.
