My issues have never been the Micro USB cables, but the ports. They seem to often not be solidly secured into the device. (Amazon's Kindles' ports are pretty rock solid, to their credit.)
IIRC the major innovation for USB-C is to put the spring loaded component into the cable rather than the device. This is brilliant, since springs wear out over time and it’s much easier to replace a cable than a device in most (all?) situations.
The problem with the ports isn't (in in my experience) with spring-loaded components wearing out: rather, like ceejayoz said, I've seen a number of cases where the port just...moves around inside the device, so that you can't plug the cable in properly. Either it gets offset, so that the port is simply inaccessible through the slot in the case, or pushing in on it just makes the port itself push further into the case. (In that case, one can generally force it in a few times before things start to really break within the case.)
I know of no specific reason why this should be more common with micro-USB than with other connectors, but I've only seen it happen with micro-USB in person.
It's more likely the solder is cracking off the PCB. Jiggling the port around forces it back into good contact and it'll sporadically work.
The real problem is we don't bolt the ports to the chassis in most cases, we just put them on the PCB with little bracing them in the direction of applied force.
As it turns out, this is addressed in the class specification. I wonder if it’s the spec that’s deficient or whether the devices in question are non compliant.
My first "hack" as a teenager was soldering a USB cable into the place the USB mini port was on a palm I was using as an ereader. The port would just become detached from the board if you looked at it funny; so this worked pretty well. I could just plug the whole device in to charge from then on.
Then I realized that the three volts that were supplied from a pair of AA batteries was really more of a suggestion. That summer, lots of gadgets I had became "USB powered"