I thought about your comment quite a lot. I don't think whether something is conscious act or not has nothing to do with causality. Steve Keen actually did some simulations according to which oligopolies can form without firms even knowing each other, just through a common pricing mechanism. That doesn't mean that oligopolies are not causally responsible for lower economic performance.
You already seem to accept that there is evidence that powerful people do not want economic transparency. This is my (anecdotal) observation as well, some of it directly from economists.
As far as economics as a profession, it's odd that (neo)classical economics held for a century despite many criticisms against it over the years (in particular the criticism that it is never really positivist). It seems pretty inline with the idea that powerful people are willing to pour a lot of money to maintain its hegemony.
Whether the economists realize it.. Steve Keen discusses this a lot. Lot of neoclassical economists did some research themselves that disputed basic neoclassical assumptions, only for these assumptions to be continued to be taught to the next generation. So lot of them are probably pretty honest, just misguided.