Well I'll probably be called a democrat too but Matt gave the answer to most of the reasons fewer deer are being seen.
They changed Habitats, they moved to where people aren't at times when people aren't, namely night time and mid day. You cant hunt at night so there ya go.

I once heard that the Definition of insanity is doing the same thing over and over and expecting a different result.

If you are not seeing deer at a specific time in a specific habitat type then....get ready....do something different!!
Switch times of days, sleep in and climb into that stand at 11 AM and hunt till 4PM. If you aren't seeing deer morning and evening in a food plot then back off the plot and into the woods. If you still don't see them morning and evening, sleep in and climb into the stand at 11 and hunt till 4.

The Deer dont leave and they dont stay bedded down in a single bed for 16-18 hours a day. They are more active during the night when pressured and/or full moons but they dont just lay up all day in a bed. They will get up and move, maybe not far but they will move.
It is unlikely they will come into a food Plot during daylight hours at almost anytime after the woods fill with rifle toting hunters. The young and dumb one may at the crack of dawn or dusk but the older ones will wait till it's good and dark.

you just gotta find them and go to where they are and be there when they get up and move regardless of the time of day.