https://en.wikipedia.org/wiki/Mode_7
The article mentions about halfway down the page that what made the 80s road rendering technique possible was racing the beam. Where say an Atari 2600 would toggle the color at certain pixel counts as the TV's electron beam swept the screen, producing graphics that seemed otherwise impossible from such underpowered hardware:
https://en.wikipedia.org/wiki/Racing_the_Beam
https://www.youtube.com/watch?v=sJFnWZH5FXc
Some engines allowed for say 8 hardcoded sprites this way by toggling colors at each sprite's position, with various rules about overlapping, so sprites would flicker sometimes when they were next to each other.