Strange. My PS3 has been in regular use since 2011 or so (the console itself being a used launch model from 2008), and I don't recall the mini-USB port on the controller ever failing to charge. I suppose I'd have to check the serial number on the controller, though, to see if it's actually that one that came with the console--I may have switched it out with one that I bought later for multiplayer purposes without realizing it.
The controller only gets charged once every three weeks or so, now that I think about it, so it could well still be under that failure threshold.
I have to agree, again, anecdotally. I have Mini cables and devices that have been in use for well over a decade. I've never in my life had a Mini cable fail on me.
I've had countless Micro cables fail on me electro-mechanically. Usually either the latch fails, not a huge deal, but not great, or the contacts "flatten" or don't contact any more.
I've lost so many that I've taken to cutting the bad connectors off and soldering new ones on since I have the tools and the skills, and I don't buy cheap cables (in the hope they'll last longer) so the rest of it is usually worth saving.
The original mini-b port was rated for 1000 insertion MTBF (I swear one friend's cellphones were closer to 500, as they were going through 3 a year.)
It was revised to fail at 5000 MTBF, much more acceptable for something that may be plugged in multiple times a day.
Micro USB was rated I believe at 10k MTBF, and moved the faily bits to the cable.
The USB-IF obsoleted the Mini-A and Mini-AB plugs at that point (which are really only used for USB-OTG, which is rare). They still let the 5k MTBF mini sockets get certified on new devices, however.
I'm aware of the ratings, I'm just trying to say that in my experience, no matter what the numbers say, reality has proved the opposite for me, I've had far more (some number I've not counted, but, in the order of dozens) Micro ports/plugs fail on my than I've had Mini ones fail (none, ever).
The controller only gets charged once every three weeks or so, now that I think about it, so it could well still be under that failure threshold.