IMUWO (In My Utterly Worthless Opinion), the prohibitive cost of recording in the days of yore ensured that nobody but a rockstar would ever set foot in a studio without fully prepared material. Each song would have been road tested in front of live audiences through multiple iterations before the tape ever rolled. Each band member would know their part cold before anyone considered recording. The songs would be so rehearsed, the instruments would almost play themselves out of habit. When that studio door creaked open, the producer cracked his face open with an inhuman grin, and the money counter started flying, the band's primary concern was getting out while they still had any money left. You tried to nail each and every performance perfectly because the money was flying out of your wallet every single minute.
When recording time is essentially free and you can have an unlimited number of takes, you've got time to play rockstar and make it up as you go. If you want to spend an entire day recording gaseous emissions (and you know you do), then you can do it with no regrets (unless you share your studio space with other family members). The motivation to make sure that the next take is golden may be missing without some other form of pressure.