"I may be showing my ignorance here about how broadband services work in the US, but what do trucks have to do with anything? Are you talking about repair/maintenance vehicles? Ultimately, what does that have to do with the price of municipal broadband?"
Most cities have large networks of cables that physically connect all the broadband customers to the providers. This cabling has many expensive fittings and the whole lot is mostly outdoors in the weather. It degrades, a lot.
Then there's lightning, uncouth birds, wayward kites, and cable piracy, all of which degrade the infrastructure as well. And to fix it all one needs a dedicated force of workers, who require large work trucks to do the job properly.
I'm curious tho; How is it done where you live? City-wide wi-fi?