The key thing is that nobody's presented any evidence, just some anecdotes. Clearly there are places that have internal competition and have done quite well, like Amazon (compared to e.g. GCP), or many trading firms.
It's anecdotes from people having experienced anxiety, toxicity and overall bad work climate leading them to either quit or seriously consider it themselves or hearing it from their colleagues.
And it's other anecdotes saying "some companies have done quite well".
I personally have experienced it and I won't go back. And I have also personally experienced the opposite and now I'm having a blast without this nonsense.
But sure, let's just say "nobody has evidence, maybe it's great, maybe it's not".
Your argument that Amazon does great does not provide evidence. Maybe they's do even better without this crap, or maybe the employees would be happier.
As someone who has read histories and has been inside a courtroom, I’m curious what you mean by this.