USB cables are disposable consumables.
OTOH the connector in the phone has a value orders of magnitude higher than its actual cost.
If your phone is perfect but the USB connector is broken, then your phone is almost worthless.
A really excellent reason to use the magnetic connector things. It saves the cable connector,
but mostly it saves the phone connector.
Very true.
Micro USB connectors tend to collect dust and crap over time, meaning that the fit may become loose. Easily solved with a toothpick or tweezers (
), but IMO highlights how bad the connector is at cleaning/maintaining "itself", especially when it's designed to be water proof, with dust really nowhere to go. I've never had this issue happen with regular USB A/B or mini B ports, albeit they were not waterproof, so any dust+crap would probably accumulate inside the device..
That's also the problem: getting inside a modern smartphone is not trivial at all. My previous Moto G had an actual backcover designed to snap off using just your finger nails. The battery was not "replacable", but you could just take the screws out and put a new battery in, or do any other work. My current S7 apparently needed to be glued allround. It's almost taken for granted that replacing the charging port on such a phone may result in a broken screen as well, which is a gigantic waste. Especially for a phone that's 1.5 - 2 years old, then a broken connector may effectively result in a total write off.
Cables OTOH are like 5-10$ and only have to last for like a month to break even. However I only had cables wear out once or twice. Some may become wiggly over time, and some plastic sleeving may break if you twist the cable too much, but the copper wiring and shield is still intact (although very dodgy looking). I actually have all of my original phone connectors end up like that after 1 years of daily use, and usually these cables are demoted to car duty.