It's a lot more complicated than comparing wages to truck costs.
To get an accurate picture of increasing or declining cost of truck ownership in terms of hours worked to pay for that ownership, the total truck service miles divided by the cost of ownership (excluding taxes & fees, financing) would be a good starting point. The fuel, repair and maintenance costs would need to be expressed in constant dollars (inflation adjusted), perhaps pegged to the truck model year, as would the wages earned over the truck ownership lifetime.
Wages are very tricky because they can change due to normal raises, or due to changes in responsibility, training, advancement/promotion, layoff, downsizing, outsourcing, etc.
The goal would be to end up with something like a number that expresses (miles of use X cost per mile) / the value of one hour of work. If that number were compared to trucks built three years apart over a 30 year time span for example, trends would be evident.
It's definitely yet another example of where the advice of an economist is needed, if Steve happens to be reading this thread.
Add: All of that completely ignores the intrinsic value of the truck; higher payload, AC, self-locking doors, more comfort. A monetary value would need to be assigned to those types of things too. Plus, I don't know how the residual value of the truck should be handled in the comparison. Is a truck with 200K miles today worth more than a truck with 200K miles 30 years ago, in constant dollars?