Maker-taker fees have existed for over 20 years since the Island ECN created the concept. For those unfamiliar with this, those who trade at the bid or ask (takers) pay a very small fee. Those who provided liquidity, or 'makers', receive a slightly smaller fee than the 'taker' fee, with the exch...
"often at inferior prices" - this is illegal in the US (see: Reg NMS). If you had proof that it was happening you would be whistleblowing, not posting it on SE. In fact, execution via those firms is typically at better prices than on any public market (the difference is called "price improvement").
There are lots of articles out on the web that explain that poorer execution can occur in dark pools. If you believe that all of them are wrong, go argue with them.
There are lots of conspiracy theories on the internet. That does not mean they are true. Here's a reputable source: investopedia.com/terms/p/… - note that the firms you've mentioned are considered "liquidity providers" and are required to "match or improve those prices [the NBBO]" if they execute the order themselves.
If Investopedia is indeed a reputable source of information as you claim then perhaps you should read some of the INVESTOPEDIA articles that discuss poorer trade fills on dark pools.
Discussion between Aaron Dufour and B…
Discussion between Aaron Dufour and B…