The question is, why does anyone take the word of a company seriously which will agree with any idea if you pay them? After several iterations of this game (decades by now), someone would surely say "nah, we don't care about these charts and whitepapers, we know that the company who made them will agree with anything for money, so it's still a NO"

My hunch is that in fact they won't agree with just any idea. There is a limit to how extreme the idea can get, though probably the filter is indeed weak. Still, without this filter, people would propose even wilder ideas that maximize their own expected payoff at the expense of other players, so just the fact that it has to be signed off by an external party is still enough information for the powerful decision makers that they are willing to fund their services.