It's very rare to have an excavation go year-round. In a few weeks alone, you'll find hundreds or thousands of items that need to be photographed, cleaned, and cataloged. And that's what we do the rest of the year: You spend a month or two digging and then 10 months daring carpal tunnel syndrome to nut up already and fight you.
When I went out on my first dig, I expected to see large walls and paved streets covered in vines and angry natives -- you know, the way ruins are depicted in books and movies. It's always something clearly identifiable as an ancient city or temple or orgy cave (depending on your taste in fiction). But then you arrive at an excavation and it's all in tiny bits and pieces, and you realize that most archaeology is making educated guesses about what used to be there based on the scant wreckage you've found. It's like putting together an enormous puzzle after your dog chewed the box with the picture to shreds and somebody stole half the pieces.
For every intact Ark of the Covenant, there are a million scattered Shards of the Something-or-Other.
Oh, and remember that awesome sonar drill thing from Jurassic Park? They shoot it into the ground and find out where the dinosaurs are buried, right before Dr. Grant trots off to traumatize more children:
"I'm starting to think our boss might be a dick."