If the price of the parts used to maintain a truck fleet increases with inflation, then it is logical that the price of the maintainers might also increase.
Inflation often results in an overall rise in prices, by raising the price of downstream inputs, such as energy or running costs.

Demanding labour suppliers swallow these price increases and therefore hide the inflation they *did not cause*, while other suppliers are free to pass them on, is to treat labour worse than other suppliers.

Which would be unjust. 

 The worst of this was shipping costs. UPS and others started adding a line item of "Inflation" to their commercial customer's label prices. 

Credit card costs are (almost)always hidden to the consumer. 

Upstream parts MFGs simply cut margins for 3rd party sales, and some even re-opening their online stores to further drive 1st party sales. 

The only benefactor is the entity who takes a fixed percentage on the price... But we don't talk about that. Weird how taxes never seem to go down.  

 Yes, funny that.