That is not a failure because it is an amp gauge. That is a mechanical failure of components due to age. There are literally hundreds of connections and components throughout a vehicle that will break down over time, exactly the same way. For example, the connections on a volt gauge, if designed the same, will fail exactly the same.
Your aged amp gauge could have easily been replaced with a new amp gauge, rather than a volt gauge, with the exact same assurance that all would be well.
The reality is, that those who have no clue about electricity, amps, volts and wiring will profess, in their ignorance, that ammeters are bad and voltmeters are good.
Plastic trucks suck...
Iron trucks rule...