I’ve been to Las Vegas twice, one in April 2017 and this year.
The McCarren International Airport is pretty large, with a mall (and of course, slots!) In my two experiences at LAS, there are several buildings. The area where Southwest is, it’s pretty small, low ceilings, almost like an underground train station, but when I went this year via American Airlines, it was as grand as I had expected Las Vegas to be. Southwest is closest airline to the baggage claim going inbound, so it was easy to think how “small” it would be.
This would explain why there is a Meridian 1 PBX for the use of airport authorities. It’s not to say that each airline and the TSA have their own interconnections, as those two are Cisco all the way.
This was taken while walking off the Jetway after landing in 2017.