I came across a video by Youtube author p-brane which seems to bring up a lot of good points,
It misses the most important point: the laws of perspective are a consequence of the size and biology of man's retina.
Human eye-balls have limits.
The size of the internal spherical surface of the retina is a limit.
The density of cones and rods on the retina is a limit.
The abilities of the cones and rods on the retina are limits.
SHORT VERSION: The retreating sun appears to meet the horizon because from that distance/angle, the sun's rays can not be discerned accurately enough with MAN's retina.
SHORTER VERSION: Man can not see forever.