That problem will always exist to some degree. We want good access to the ability to repair (in our laws, in how things are engineered or designed, in our supply chains and in industry support, in our cultural expectations, etc.), but there will always be certain types of repairs that will cost more than manufacturing a new one from scratch.

Sometimes repairing some component will take more work than the entire component is worth. For example, the extreme example of a stripped screw shows us that replacing a stripped screw is cheaper and easier than trying to re-machine that same chunk of metal back into a screw shape.

Or some types of breakage just can't be repaired practically. A torn piece of paper can be taped back together, but it isn't quite the same as a new piece of paper.

Or the repair might require work done on a particular place that makes that labor more expensive. Welding a leaking pipe might be slower and more expensive than replacing that pipe, if the leak happens to be in a place that is hard to access. Or, as you learned, paying for a repairman to drive from one place to another with the right part might cost more than just the general cost of delivery of the whole thing.

Often, troubleshooting will take a skilled troubleshooter much more time, and their time is worth more than the cost of replacing the broken thing, perhaps by a less skilled technician.

As the price of a thing goes down compared to the cost of the labor to fix it, the calculus of whether a particular repair is worth the cost is going to shift towards replacement rather than repair. And that's not always a bad thing, as it usually means the thing is getting more affordable, or people's time is getting more valuable.