Mini and micro USB (and I presume USB 3.0) are all rated for much more plug cycles. I'm sure most USB 2.0 plugs made now are actually rated for much more than 1500, but you can't exactly go about changing the spec now can you?
Mini USB has about the same robustness as big USB. It is micro USB that is much more robust, which is one of the reasons it was chosen for the European phone charger standard.
I know people who have worn out their connectors. It's not a common problem, but . . . surely we can do better.
Too bad we can't get power over optical connects. Practical amounts of it, I mean.