That guy is good ... and he's wearing the world's greatest, alltime winningest, sports franchise NY Yankees cap.
Wouldn't FoK or AoN orders work around this issue? In the video he quotes the order being routed to the exchange with the least depth. If the order was routed to the exchange with the most depth, it would seem possible to avoid giving enough time for the MM's to change the price.
Interesting but I don't see conspiracy. The higher the volatility the wider the bid ask spread. As a guy who spent some years with a market making firm in commodity options the busiest days in terms of lock limit up lock limit down were often the most profitable days because the bid ask spread widens. Is the usual b/a spread was a 1/2 cent in soybean options on days with vol exploding and big swings those spreads would go to 5 cents wide. Nothing shady about it the MM has to hedge in the futures or underlying and with it bouncing around all over your delta hedges aren't clean but you're locking in more profits with the edge in the option premium. And floor traders would always lean on brokers order deck. If you knew they were offering at a certain price you'd wait for the futures to move and know that order was there you could come back and hit but once the price was right. And yah if you had some balls you might hedge it before you even buy it as you know you're going to get a piece. Without MMs there wouldn't be anyone for retail traders to trade with.
Those very same points ... were made in the video. Who said anything about a conspiracy - in this topic.
Concerning stocks, it use to be you HAD to buy/sell in lots (100) shares...Unless you asked for less and it would go to the back office (different exchange...Secondary market) to get filled. Now the "all or none" has become a total headache!! You don get filled at your price (limit) with a "all or none". So, you end up with stupid odd lots. You HAVE to buy more shares at a higher price. And you get these multi amounts of odd lots (1 share/10 shares). I want to buy in the hundreds to get my full lots to do covered calls. Headache at the end of the year having two or three entry prices (buys) when it's time to pay the tax man. Again, "all or none" no fill, no conditions...Partial fill!!