At the risk of being run off, let me suggest that what this comes down to is the type of hunt you are looking for.
If you are interested in maximizing the number of animals you can see and shoot in a day, then South Africa (and Namibia) is the place to be. By and large - not universally, but by and large - the hunting in South Africa will be vehicle "driven" (pun intended), meaning that you will typically spend more hunting time in the vehicle than on foot. This does not mean that you will be shooting from the vehicle - although in South Africa that is quite acceptable, with vehicles set up for it. At the end of the day you will return to what is usually a very nice lodge or other permanent structure. I could go into the economics of day rates and trophy fees and who owns the game and gets the trophy fees, but I will leave it at that for the moment. You can "get away from it all" in South Africa, but it isn't easy. Hunting vaal reebok on foot in the mountains of the Karoo is one example.
If you are looking not to maximize the number of animals you can see and shoot, but rather are looking for more of what I might call an "olde tyme" African adventure, then there are places where that can be had, but they tend to be very remote, to be on state land, and often (but not always) to lack permanent structures. Examples would include forest (jungle) hunting in Cameroon - you will likely never see (much less shoot) an animal (or anything else) from the roads, but rather you will spend your days inching through thick jungle with visibility measured in feet rather than yards, in hot, humid air which does not move, surrounded by insects and other critters which want to bite you, sting you or suck your blood (or all three!). In fourteen days in the jungle I fired my rifle three times, on a grand total of two animals (I did beat a gaboon viper to death with a stick, but that's another story). The hunt was a great success. In Ethiopia to hunt mountain nyala you will need to get to high altitudes and will likely be living in temporary tents. You may drive to a hunting area, but then will have to walk, sometimes long distances, on precarious mountain trails, often in the dark, and you may well spend your day without seeing your vehicle again. I could give other examples.
So yes, if your comparison of apples to apples is volume of animals taken at the lowest cost, then Zambia, Tanzania and other similar countries may appear to be pricing themselves out of the market. But make sure you are comparing the same things. As I've mentioned, I provided a breakdown of the costs of hunting in Benin versus South Africa, and depending on the number and type of animals you are taking, Benin may well end up being much cheaper than South Africa (because trophy fees on "expensive" game tend to by much lower in these countries.)
You could see the more expensive countries as "paying more and getting less" but that would only be correct if the "getting" you are comparing is animals. If what you are looking for is a real wilderness adventure in a world where those are far too rare, then you may be paying more in some countries, but what you are getting is priceless.