If that is all true, why is Arizona conducting the audit by looking at all the ballots themselves?
Air gapping is nice but has a theoretical weakness. A computer with a sound card can be hacked via sound waves. Air gapping isn't perfect.
https://www.insidescience.org/news/computers-can-be-hacked-using-high-frequency-sound#:~:text= Computers Can Be Hacked Using High-Frequency Sound,history also suggests that countermeasures will... More .
But that isn't the biggest issue. There are a couple others. I have seen machines with privacy shields and ports. If a voter has the curtain drawn, can they access the voting software through the ports? The companies of course say no, but are we sure?
But even more than that, since I am currently taking a quick break 2/3rds the way through The Godfather, if Don Corleone wanted an IT guy in NYC to slip code into a hundred machines being deployed, do you think he could have arranged for it?
We are lucky, right now there is no proof machines have ever been compromised and no proof of your ineligible voter issue. BUT we know Russia, China, and others, would love to corrupt the system. I'm not too worried about the DNC or RNC hacking our systems. I'm not sure they could have a combination lock that uses only one number and there being one number on the lock. But the Russians or Chinese might opt for something, and they are a bit better. They might hire 100,000 people to vote illegally, but that is hard to hide. Someone is going to talk. But getting to a few voter IT people in some swing states? A bit more possible (and even then pretty unlikely).