I predict that Michigan is going to out-California California in the next five years.
Sadly, you are probably correct.
What needs to be done is a complete overhaul of the absentee voting process, whereby if you choose to vote absentee, you lose your right to a secret ballot.
Your signature affidavit will be numerically tied to your ballot, so that if the signature is later successfully challenged the associated ballot's votes can be subtracted from the totals. For privacy, only elected county clerks will have access to the list of absentee voter names and their associated ballot numbers, not volunteers.
With today's system, once the outer envelope with the voter's signature is separated from the ballot inside, there is no way to subsequently retrieve that ballot if the signature is later determined to be fraudulent.