I think most people would prefer no voting machine software at all, seeing how most people can not "verify that the machine is really running the code it is supposed to run" but can indeed verify a paper ballot.
And of course signing a huge code bundle is the farthest possible thing from "run exactly the software you think it runs". Console manufacturers keep learning that. You really wanted to run that WebKit version that turned out to instead be a generic code execution widget? Think again.
The reason I bring it up is that one of the benefits of open source that is often mentioned is the ability to verify that it does what you think it's doing. Doesn't matter whether it's a voting machine, a self driving system or an ATM or whatever. It's still good for open source to have the capability to do this kind of proving in cases where you want it.
The majority of people, with normal sight and no mobility impairment, may be fine with paper ballots. But for some of us, an accessible voting machine is more than a convenience, as it enables us to independently (and therefore privately) cast our votes.
Even a mobile app to guide blind users on the ballet would be more secure.
Basically excludes any black box machines, block chain, cryptography and any existing computers.
For example voting machines should be done in this way. Open source software such that outsiders are able to verify + a secure boot process such that anyone can verify that the machine is really running the code it is supposed to run.
Of course we should all still be very careful of what we accept in terms of control of our hardware. And I agree with you that things are not moving in the right direction there, with locked ecosystems everywhere.