Back when computers first appeared applications had to be loaded into memory from floppy disk.
And I remember conversations with my father who programmed in the late 1960's.
He said they really had such limited amounts of memory that they really had to conserve it.
Fast forward to now, when programming for the mobile, you really have to conserve how much activity you do as to preserve battery life.
Things change over time, yet they remain the same.
We used to have centralized mainframe, then PCs, then client server, then web, then Cloud - full circle again.