well I can imagine many reasons
from low deer numbers, or the fact, deer learn over time and well, food changes over time
so, sitting in a deer blind that deer know is there, after the first day when shooting starts, many deer any more go nocturnal and smarter one's avoid places they know humans be at
all the more so folks cabins and decks and campers!
just cause a spot was good for a while , doesn;t mean it will be good forever!
things mature and alter again food sources and patterns of deer
pressure changes there movements

this is why its called hunting, you have to some times HUNT for the best places to find them at!

also keep in mind, OTHERS in your area might be adding food plots or other things drawing deer OFF your area and into there's!

one farm I managed ,it was nothing to see a 100 plus deer in its field and plots
BUT
go a mile down the road, and you couldn;t find a deer TRACK< never mind a live deer!

food is a powerful thing in the worlds of wildlife!