It's a bit concerning that people believe a hollywood movie has taught them how the industry works. Keep in mind how hollywood portrays "hackers" or "scientists" or "Russians" or whatever group is an outsider or opposition to the protagonist and realize they're doing the same to finance.
I worked in the mortgage/CDO/CDS industry for 10yrs during that period (2005-2015).
If anything, the movie was too positive. There aren't as many players like Steve Carell's character who are worried about the world, they are usually worried about how to liquidate their book at the right time.
The bit about getting marked the wrong way was especially spot on.
Another very accurate movie: "Margin Call"
Jeremy Irons is fantastic in this film. The entire board room scene is amazing.
The 3rd one is 99 Homes. The key line is: "Don't get emotional about real estate." What is sold as a place for family memories for some, is just another asset class for others.
OTC or seldom traded securities may not operate in the same way that a highly traded stock like Apple does from a price standpoint. For a boutique security that is created for a customer, the price is whatever the market is willing to pay - but the discovery of that price can quite literally happen over the phone because in the market there might only be one customer and if you sell to them... that's the price!
So assuming that Michael Burry (in this instance) actually had Goldman Sachs create a boutique security, price discovery may very well have happened over the phone in just such a manner. I don't know the details but I'm also not sure why you would think that this can't happen? Please feel free to educate me. I don't know much about professional investing either.