Yep. And in Nashville, where most of the artists you mentioned record, they're not only using Pro TOols, but they're using analog mixing consoles, which run up into the hundreds of thousands. Also, note that the session cats they bring in have years of experience with their instrument, not only playing it, but knowing how to dial in that right tone. A drummer may come in with 8 or 10 snares, so the engineer can hear them all. A guitarist may come in with several guitars and even a collection of amps. So like he said. The variables are so limitless, that we can't even scratch the surface of what these guys are doing.
Kevin