At the end, the professor writes about the fact that lower income folks typically have variable income levels, yet still have to pay rent, forcing them to resort to payday loans.
There is a startup called Even that is trying to help with that problem: https://whatiseven.com
This will not cure any "low income folks" woes. Simply averaging the paychecks will not help the fact unexpected issues arise... or the fact that they don't earn enough to live a simple life.
They aren't simply averaging; they expressly state that "average" is used loosely and they are using an undisclosed algorithm that is not a mathematical average.
Even expressly does not provide loans; since it uses an undisclosed algorithm to calculate "averages" that are expressly not actual averages, they can probably guarantee that they are more likely to be taking in funds that are above the "average" than paying out for below "average"; with an undisclosed algorithm, they could even guarantee that you can never receive more in "Boosts" than you've paid in previous deductions.
They also don't seem sure what their fee is -- their ToS says $5/week, other parts of the site say $3/wk.
It depends on the loan size. If the loan is $1000 then that's 1.2% interest per month. They can make money with that, and maybe their average loan size is smaller than that in which case the effective APR is even higher.
There is a startup called Even that is trying to help with that problem: https://whatiseven.com