LP's or long form collections by artists capture a moment in that artist's creative point. Typically, the cycle was release a record, tour a bunch, write new music, and repeat. This meant by the time that next LP came along, the collection of songs on there could sound fairly different as the artist changed, got better, heard new songs and got inspired etc.
Then there's the recording and engineering challenges around mixing and mastering an album. Albums need to sound cohesive even if the songs aren't necessarily the same genre even. The best albums are those ones that flow between softer or more upbeat music but still feel tied together as a whole.
Forcing artists to pump out strings of singles and EPs diminishes music as an artform. It takes away the format that's allowed some of the best modern music to be created that likely would never have been created if artists were just constantly pumping out individual disconnected songs.
Even today, you can still find some pretty amazing albums that are being made where each song individually would stand as less, but together as an album they come together to make some great art.