My county of over 600k people has a Bureau of Elections staff of five, and none of them are really technical people, they just do basic work on the machines and train the temp staff hired for elections. They rely on a contractor to handle just about every aspect of the technology, including the pollbook system, and that company is a larger operation but still the kind of operation where I've heard the elections staff getting on the phone with them to have them restart a service that had gone sluggish. Some amount of support is provided by the secretary of state, but the SoS elections office is also very small, and even the state's department of IT doesn't have a meaningful security department.
I honestly think that the election system in the United States is simply too decentralized. Counties, even larger ones like mine, struggle to afford to hire a staff or retain contractors that have any kind of serious security expertise - or even expertise in reliable services. The federal elections commission was created to address some of these problems by providing centralized resources to states and counties, but it hasn't gone nearly far enough in my opinion. I have a had time imagining a way to make a serious improvement here without moving just about the entire platform for voting systems under the federal government.