Number of vans is up.
The economy is down.
Something has to give.
A carrier has 400 units and gets 200 load offers.
One day...half the fleet runs. The next day...the other half runs.
It is known as income averaging to keep drivers hanging on...sort of like "Unemployment Compensation". Just enough money to cover a few expenses, but not enough to make you stay unemployed.
And that is why you see so many trucks for sale and a new group in orientation every week.