"Your examples are all less scalable and easier to detect that hacking."
Less scalable likely yes, but easier to detect depends. How would I know, if my local vote regulator is a russian asset?
"You have only their word to go that the published source is what is actually running on the machine in front of you in the voting booth."
That can be changed. In a way, that I also can voluntarily help with the voting and vote count today, you could have community based people overwatching the technical deployment of the machines.
I am not saying, that what the swiss are doing is enough. But I like voting and I would like voting to happen more often. That would be way easier with digital secure solutions. We can transfer our money digital securly, so why not also our vote?
(well yes, anonymity of vote makes it harder, but not impossible)
More voting, more democracy.