inspect the inside and outside of the truck before and after each trip.

This could easily be a full time job for a team of people who working an ordinary 9-5 job inspecting one truck after another all day, basically the way taxis and other car fleets are maintained.

I'd argue that's an improvement over driving a truck. Truck mechanics are paid slightly better than truck drivers, and they work far better hours.

Many of them can fix blown tire or a failed spark plug

Trucks have 18 wheels. A tire doesn't have to be fixed immediately. And I can't remember the last time I encountered a failed spark plug... but even if it were to happen one cylinder being out of action will just reduce your horsepower by 12%. You'd fix it after delivering the cargo.

But again, roadside mechanics are a thing. And they're paid even better than workshop mechanics.

deter theft and vandalism by often sleeping in the truck

Human truck drivers are only allowed to drive 60 hours a week. Which means for at least 108 hours a week, the truck is parked somewhere. A self driving truck would have no such limit, and would almost always park at a safe location.