We voters in British Columbia have tested the theory "early voting increases turnout" in 7 elections from 1996 to 2020. Voter turnout did not ever return to the 75% level achieved on the single Election Day in 1991. It is now an historical fact that early voting does not increase voter turnout to the level achieved by one day voting.
Early voting was and still is an easy solution. All it takes is a change in the procedures. It's too good to be true.
The hard solution is based on voter engagement in the political process. And a consequential way to engage voters is when everyone in the community votes in-person on a single Election Day.
It's the way we used to hold elections. Election Day got all of the attention back then. It was necessary since there was only one day to vote. Yes, it was inconvenient. Yes some employees who got 4 hours off with pay didn't need that much time to vote. And yes the media hyped it up big time. But it worked then and it can work again.
I prepared the schematic below based on our 10-election experience over 37 years to demonstrate the 7-election failure of early voting to increase turnout back to 75%.