>And if you're in a position that requires you show up for work at a certain time or lose your job
You can vote on your way home or wake up early.
>and your commute requires 90 minutes of bus rides, and your polling place is not on your bus route, how do you go to your polling place?
Not sure about all states but California has been allowing people to vote in different polling places then their own.
If this becomes widespread it would eliminate this part of the issue.
>And should there be some issue with your registration, and you need to go all the way to the county courthouse to file a provisional ballot...
This would also be an issue with mail in ballots. Your vote would either not count or you would have to go in.
>There are plenty of people for whom actually making it to a polling place can be a challenge; just because it's easy for you, who is presumably a salaried worker commuting by car to a workplace that doesn't mind you showing up ±several minutes from regular working hours doesn't mean it's easy for large portions of the population.
You can go after work as well. Many polling places are open until 8 or 9.
In California they have the polling places open for multiple days prior to the election as well. I am not sure how wide spread that is outside of California.
Just to be clear I am in favor of making voting day a holiday. Some people still need to work (doctors, grocery stores, police, etc) but they could be given a few hours of paid vacation to vote. I think this is a better solution than mail in ballots.