[philman_36]

That diagram does not work.
Yes it does.

The sun would never set.
Correct. What it DOES do is move out of your field of vision. An airplane that disappears past the horizon isn't setting either. It's still traveling at the same altitude only it has moved past your visible range. THAT is perspective, not what you think it is in your attempt to explain crepuscular rays below.

Sierra Nevada Sunset + Night Sky | Timelapse Astrophotography
The fading of the light and encroaching darkness.
The sun's light diminishes as it moves away from you as there is a limited throw of light just as the model shows.

Crepuscular rays are an example of perspective.

That statement illustrates that you have NO clue about what you're saying.

Beams of light from a light source. Nothing more, nothing less.
A CLOSE light...well, you see the effect.
Close street light + trees = crepuscular rays.
Close sun + clouds = crepuscular rays.
NOTHING WHATSOEVER to do with perspective.

[Nateman]

As an airplane moves out of your field of vision it shrinks to a point. Why doesn't the Sun do the same? It keeps that same disc size all day long before it tucks itself under the horizon.

You confuse Crepuscular rays from a nearby source with one from a very distant source. Seeing them does not necessarily imply they are from a nearby source.