I have a road bike with a front brake that wears a lot of brake pad when I ride downhill every day. I lose 900ft in elevation on steep grades with lots of stop signs and traffic lights. On top of that, it rains a decent amount and the rim brakes are terrible in that weather. I don't trust them downhill in the rain. Sometimes I just walk.
I feather the brakes going downhill, because otherwise I'm too fast to stop quickly for an errant car.
It'd be nice to not constantly replace pads, and have powerful stopping. How can I make this constant downhill more pleasant?
Have a look at installing Cantilever brakes- larger pads so you can retain the same stopping power and increase life, at the expense of a few grams of weight. Cantilever brakes will also help in the wet due large pad (more surface area). These are the preferred brakes for tandems and tourers - you may have trouble getting decent quality ones these days. As I understand, V brakes are not compatible with road bikes without adapters and are not always as successful as you would think.
Discs would be the ultimate wet weather improvement and provide the stopping power you want, but I would caution against hydraulics for such big downhills. They have been known overheat and boil the fluid - you get instant total failure when it happens. Apart form this, you need new forks and wheel (minimum of a hub), and probably new levers, so the cost may be prohibitive.
You can replace the pads (as stated elsewhere). There are a lot of variations in pad material, and a faster-wearing pad is not necessarily a better braking pad. Unfortunately, it's hard to find a good selection of pads, and even harder to get good info on which is suitable to which conditions.
You can use your rear brake more, especially for speed control, and save the front for more "serious" efforts. When I'm on a downhill (rarely as steep/long as yours, though) I like to alternate between front and rear brakes for speed control, and I do it more in bursts rather than with steady pressure. I'm not sure if this is "approved" technique, but it's what makes sense to me.
You can install a second set of calipers. This is often done on tandems, and can be done simply on some bikes/with great difficulty on others. (Of course, you'd need to figure out how to operate the extra set, without growing a third hand, and you do have to worry a little about the rim overheating.)
You can get disk brakes (though from the war stories I hear here it's not clear that they are really any better in such a situation).