Many of Lee/Ditko's early tales were similarly self contained. Reboots wouldn't be half as necessary if more epics had a begining, a middle and an end contained within the span of 17 pages.
I've heard that Stan's attitude was something along the lines of "Every comic is some one's first comic"
I stopped buying a lot of stuff back in the eighties when I was first setting up house on my own and other things had to take priority.
Never managed to find my way back into the Marvel Universe after that, multiple part stories and reboots really screwed it up for me.
Prof