Yeah, possibly. What is indisputable is that the mooted replacement (the F-35) is as useless as tits on a boar for close ground support.
An aircraft like the A10 (and a helo like the Apache, as noted below) has a huge benefit over a drone in its ability to stay on station. As also noted above, other aircraft like F16, F15, etc move fast and generally come in, take out a single target, and move out. A10 can circle, move slow, and continue taking out targets as they appear.
You may take out one or two armored vehicles visible on the battlefield, only to have more pop up over a ridge after your CAS has departed. An aircraft that can stay on station has a tremendous benefit.
Survivability of course matters in something like Close Air Support, with a long on-station time. As I recall, the armoring on the A10 is staggering (Wikipedia says 1,200 pounds (540 kg) of armor just for the cockpit and main aviation systems).
With the Apaches as well, the advent of the Longbow mast (360º radar mounted above the main rotor) after Desert Storm gives it an incredible ability to stay out of view, and pop up just long enough to get a weapon off. I believe the concern with attack helicopters though is tremendous susceptibility to fast movers, and even ground attack by RPG (Al Qaeda in Somalia perfected the art of short fuse detonation of RPG rounds near the rear stabilising rotor. See: Black Hawk Down)
Infantry support seems to be something that historically the military continues to forget until they suddenly need it, and scramble to stopgap a solution from whatever is laying around. It wouldn't be surprising if the A-10 comes back from the dead in some future conflict for just that reason.
airframe per airframe, sure.
dollar per dollar (either production costs or operations/support cost)? Less likely.
Typical payloads on MQ-9 Reapers go up to 4 Hellfires and 2 500 pound bombs at one time. It's still a lot less than an A10 but it's enough for many situations.
[1] http://www.vanityfair.com/politics/2013/09/joint-strike-figh...
There's a very good reason why there were so many specialized aircraft in the first place.
Which it can't, of course, but since admitting that would require keeping the other planes, which would require canceling the F-35, which can't happen, everybody has sort of agreed to pretend it can.
Hope we don't declare victory with the F-35, field it, and then suffer in our next serious war....
In the year 2054, the entire defense budget will purchase just one aircraft. This aircraft will have to be shared by the Air Force and Navy 3-1/2 days per week, except for leap year, when it will be made available to the Marines for the extra day.
(From Joseph Tainter)
Diminishing returns to complexity. Drones would, of course, be one way of addressing this phenomenon.
Our airforce is usually a bit more than 100 fighters. Always has been. Now we're going to get about 30 F-35s, and they're going to be slower and less maneuverable than our old F-16s. But they have stealth, and some other fighters that we don't have can take off and land vertically, so it's all good I guess.
I seriously think this is going to be the end of western air supremacy.