Rankings deal a great matter for ~98% of the roster. A select few (Conor, Nate, Khamzat etc.) will be given opportunities they have not earned because they are (potentially) big money-earners, but it does not render the rankings obsolete for the overwhelming majority. Michael Chiesa, Derek Brunson, Arnold Allen - guys like this are not going to be gifted anything. They're going to have work hard and put up great results and build win streaks to get close to a title shot - if that's something they care about, and for alot of them they do indeed care. You better believe alot of the rank-and-file guys who step into the cage care about their rankings.
The exceptions don't disprove this.