Fair enough. As far as repairing the motor goes, it's pretty much like any DC motor, so both the brushes and commutator are going to wear and get dirty. So maybe it just needs a cleaning and a new set of brushes, but maybe the wear to the commutator is such that it has to be replaced, and then you're futzing with the windings, so this is all stuff best left to shops that specialize in... wait for it... motor rewinding. Sure, they used to do more of it here, but now it's a more disposable globalized society that doesn't want to pay North American rates for that kind of service, so "Mexico". While I'm certain you can find someone locally who does that, I doubt you're going to want to pay them some multiple of the cost of a new starter. Just how it is.