This is hilarious to me because you are basically making the correct point, but with the wrong conclusion. Let's take as a potentially erroneous given that early voting worked perfectly OK. Then, in 2020, it's run exactly the same, but demand is larger than in previous years [0]. That might result in exactly what's being reported here.
So yes, Apple made a mistake with a novel experience. Looks like various supervisors of elections are maybe also making a mistake with a novel experience. But I the latter doesn't get the same slack as Apple?
And, to be fair, at least my local supervisor of elections sent extra mailings this year making it abundantly clear that mail-in voting was an option and how to register for it. So they did make obvious the availability of the preordering equivalent.
[0] I won't say larger than anticipated, because the likelihood is that no one bothered to anticipate at all. Otherwise they might have figured to open more early voting stations this year.
Election administrators are pretty good at projecting turnout. Historical data and all that. In the year 2020, there's exactly no reason any jurisdiction should have anything less than perfection running poll sites.
The only slack (goodwill) I'm willing to grant admins this cycle is the massive pivot to postal ballots on short notice, while fending off widespread sabotage and harrassment.
Postal balloting is very different from running poll sites. Oregon and Washington experienced a lot of growing pains. And they made the transition gradually. Even so, our admins experienced a lot of burnout.
I imagine OR and WA admins are in a lot of Zoom calls with noobs nationwide. Alas, some jurisdictions don't want to learn.
I expect 2020's election to be the biggest fubar imaginable.
Generally speaking, commercial enterprises are more accountable to customers and efficient than state endeavors. Fanatics still line up and camp overnight to obtain a new iPhone when they are first released.
That said, I've never waited more than a few minutes when voting on election day in the US.