Did you ever publish anything? First year or two it is mostlu pushing marketing/pr, and the long tail of trickle of money is where the true earnings lie. Also, for many works of art it takes more than 2 years to produce a next piece, and even if it was less, it’s not sure if it will actually sell.
Anything below 5-10 years and you have literal starving authors. Anything less than 5 and you may as well abolish it altogether.