Why does it take a week to count ballots?
Some states allow for mail-in ballots to arrive after Election Day, as long as the ballot has been postmarked by Election Day. No surprise, California’s is pretty liberal: three business days after Election Day. Since Friday was a Federal holiday (Veteran’s Day), they are allowing the ballots to be received by today. It is believed California will start counting them tomorrow.
I’m not sure what Michigan’s policy is for mail-in ballots, although there are the military overseas ballots to be counted. But Michigan has counted nearly all of that state’s ballots. In comparison, California’s mail-in and provisional ballots will account for something in the neighborhood of 30% of that state’s votes.