This [1] is a painting from 1476. Notice how architecture and landscape has depth, but people are all +- the same size except for Mary and God.

You wouldn't want to draw mere mortals bigger than saints just because they happen to be closer. Peasants (which couldn't read and were the main target of these paintings) could get wrong ideas.

https://upload.wikimedia.org/wikipedia/commons/f/ff/Francesc...