[kayfox]

Airlines don't negotiate prices based on the exact options selected, they select a list of options and then negotiate on price from there. This particular option does not appear to have a price associated with it, it just increases the cost of training and documentation for pilots and some airlines would opt out of using it.

People talking about MCAS seem to simultaneously pound the line that everything on the aircraft the pilots encounter should be trained for and forget that adding new stuff to the flight displays will incur additional training that an airline may not want to deal with.