This is not a significant phenomenon driving rent increases. You make more money if you defect from this arrangement and real estate holdings remain diversified in America.
Also - setting rent in a given market is a game that the same landlords play with each other, annually. Strategy is different in multi-round games.
And - back in the 1990's, I knew a few residential landlords in a mid-sized college town. They clearly said that they got together annually, and decided how much to increase their rents.
Not good, certainly, but absolutely in no way driving the current rental crisis.
Would love to learn more about this software.