While land and resource availability are definitely reasonable concerns in any discussion about, say, shifting humanity's primary energy source to direct solar

While land and resource availability are definitely reasonable concerns in any discussion about, say, shifting humanity's primary energy source to direct solar (lots of panels means lots of factories to build them and lots of land to put them on) as opposed to indirect solar (oil and coal) I'm struggling to understand why you think "thermodynamics" means that usable energy will become scarcer on a timeline that is meaningful to human civilization. Happy to listen if you care to explain, but no worries if not.