,,, during the course of an album they can have half the country in on sessions until they get just the sound they want. Some players have it and some don't from track to track. A whole new band could be put together after lunch for a new attempt at a song that could take weeks to get right. The year long effort in putting down "Aja" is a good example.
I'm sure enema-m would roll out of some ninety foot limo after sniffing glue, trip over all the gold chains and hookers at the studio and blurt out his funky square dance calling in one take. In three words, exceptionally easy money.