scottc wrote: That's a pretty poor argument. 25 years ago, everyone ran DOS on their 286s and Linux hadn't been invented yet. Why don't we just use those anymore?

It's not even remotely the same argument.
Program modes are fine, and I use them extensively. The problem is, cameras are still relatively stupid, and one size does not fit all. There are lots of corner cases, and specific ways of dealing with them, such as: Backlight - use fill flash and/or increase exposure. Motion blur desired - use Tv (shutter-priority) mode, let the camera pick the aperture. Depth of field is key - use Av (aperture-priority) mode and let the camera pick a shutter speed. Astrophotography - your meter a shit. I don't care how good the camera is. Go full manual and lock the focus at infinity. Look at your results. If you don't have time to look, bracket the hell out of everything. Letting the camera bracket for you is fine, but you should understand what it's doing and why. Macro - you need to be manually focusing unless it's time-prohibitive (moving insects or the like). Your depth of field is likely measured in millimeters.
Basically you don't have to know what the operating system is doing with the bare metal to get the best results, unless you're programming for raw speed. You
do need to know what the camera is "thinking" if you want to get optimal results, and the only way to do that is to do all the thinking yourself for a while before handing some of it off. I don't mean you have to spend years or even months in full manual. A couple weeks is probably quite adequate, provided you go out of your way to experience those corner cases where you're going to have to do the piloting yourself.
If you never step outside the box of taking family photos and technically undemanding travel photos, you can get away with just pointing and shooting, but why close yourself off from the power of taking control when that's half the point of having a rig that can give you that control? In order to be able to wield it properly, you have to practice, and cost is no longer a reasonable objection in the digital camera era.
Program modes work well within their (admittedly quite common) limited use cases, but even so, you need to have a grasp of what's going on in order to pick the
right program mode. Think of the modes like a set of overlapping circles. If you're in the middle, it probably doesn't much matter which one you pick. If you're out toward the edges, it becomes crucial you pick the right one. And if you're WAY out on the fringes (using what should be the biggest circle of all, your own ability), you're going to have to do it yourself.