Looks like the calipers were ground all the way down. That's pretty weird for 2 years and 20,000 miles.
Well, one possibility is you have an inherently challenging driving environment, e.g. you drive around Manhattan all day. Even a sensible driver would use brakes that fast there.
The other possibility is that you drive roughly, either due to lack of skill, or strong expression of personality via driving style.
Once I was tailgated for a moment by a Mustang. The guy was trying to go 90 mph but couldn't due to medium-heavy traffic. The Mustang would race up to people, tailgate, snap across lanes, get boxed in - all emotions no strategy. I kept up with the Mad Mustang for ten miles without tailgating or cutting anyone off (and obviously not hard accelerating since I had a Geo Metro). It was unbelievable just how unproductive the drivers' "Mash the gas mash the brake" bad attitude was. I was doing the same thing with no brake wear since I was thinking ahead. That's not incompetence, it's testosterone poisoning, driver was all attitude.
How to beat it
An important secret: brakes destroy kinetic energy. Kinetic energy is the square of speed. 50 mph has four times the kinetic energy of 25 mph. 75 mph has 9 times. You buy kinetic energy by buying gasoline. You throw away kinetic energy by using brakes.
Capische? When you press the brake pedal you are destroying kinetic energy you paid for. So, now let your thrifty gene kick in. Do I need to apply this power (gas)? What if I don't?
For example, a traffic light is 1600' (500m) away. If you have a high level of situational awareness, you know about the light and know it is "stale green", you're not going to make it and are likely to need to stop. Thus, you can get off the gas right there and coast up to the light. When you do brake, you are braking from 30 mph (50 kph) instead of 60 mph (100 kph), meaning 75% less brake pad wear. You also save the gas not burned. You may also get lucky and have the light turn while you are still coasting down, then you use your judgment as to when to speed back up so starting-up traffic is not in your way. It's often possible to not brake at all.
Of course many people only focus their attention 300' (~100m) ahead or so, and so they cruise most of that 1600' (500m) with foot on the gas, only braking to avoid hitting stopped traffic ahead. This is hard on the brakes.
"Hypermiling" is the name of techniques designed to save gasoline. The single best way to save gasoline is not invest in kinetic energy and then immediately burn it up in the brakes. Thus, many "hypermiling" techniques are also excellent for reducing brake wear.