What your entire argument is ignoring is physics. The *same* atmospheric conditions that affects your 200 yard zero also affects your 100 yard zero, albeit to a lesser degree. If atmospheric conditions change enough to move your 200 yard zero by 2", your 100 yard zero will have shifted by probably an inch or so, and your 1000 yard dial will probably be off by 10" or more. In that scenario, it wouldn't matter what your zero range is; if you fail to adjust for current conditions, or do not have accurate data, you are unlikely to have a good engagement.
Example - 162gr 7mm ELDX with a G7 BC of .318, MV is 2940 @ 28°F. Zeroed at 200y, with a DA of -1500' (typical of my hunting conditions). At 100 yards, I am 1.3" (1.2 MOA) high, at 300 my POI is 6.7" (2.1 MOA) low, at 500 I am 37.3" (7.1 MOA) low, at 1000 I am 259" (24.7 MOA) low. This is according the "Shooter" app (developed by Bryan Litz), and verified on paper to 700 yards.
If my conditions change, and my new DA is 12,000' (temp remains 28°F), my 100 yard POI is still 1.3" high. My 200 yard impact is still 0. My 300 yard has shifted to 5.9" (1.9 MOA) low, 500 yard is 33.3" (6.3 MOA) low, and 1000 yard is 212" (20.3 MOA low) this is again, calculated using the Shooter app, although unverified. Based on my established DOPE though, I have no reason to believe any substantial error exists in these calculations.
Conditions change *again*; this time we have a DA of 2500' and a temp of 85°F. Due to the increased temperature, MV is now 3006. These conditions are consistent with my mid-summer target practice. 100 yard POI is 1.2" (1.1 MOA) high, 200 yard is .1" low, 300 yard is 6.2" (2 MOA) low, 500 yard is 34.4 (6.6 MOA) low, 1000 is 233" (22.2 MOA) low. This is again calculated from the Shooter app. Since I am unable to hold .1 MOA from a field position, the data inside 300 yards is "unverified." However, I *can* hold .5 MOA pretty consistently, and the data from 400-740 yards has been verified as accurate.
What is the take away from all of this? Your zero range is not relevant. What is relevant is that you have a system. This system needs to be capable of gathering and logging accurate data, *and* verifying it against whatever ballistic calculator you use. Put garbage into your system, and it will produce garbage results.
With *my* system, my rifle, and my load; a change of 55°F AND 4,000' density does not substantially effect my trajectory inside of 300 yards. With this in mind, I zero at 200. From 0-250 I can hold dead on (elevation) and expect to impact within 3" of my POA. from 250-300, hold for a high shoulder shot, and I'm still good. Beyond 300, I need accurate data regarding my current atmospheric conditions. This level of precision is more than acceptable for me with my style of shooting and my style of hunting. I am not shooting 1" "X" rings. I am shooting 14"+ vital rings.
Would I travel from my "comfortable" -1500' DA to 12,000' and fire at a game animal? Not if I could avoid it. I would make every effort to validate my calculations in the conditions which I will be shooting. However, based on my already established and verified DOPE, I feel reasonably comfortable that the calculations provided would be accurate enough to be effective at the ranges I am willing to shoot.
PSA: Listen to the pro's
"Beyond 300, I need accurate data regarding my current atmospheric conditions. This level of precision is more than acceptable for me with my style of shooting and my style of hunting. I am not shooting 1" "X" rings. I am shooting 14"+ vital rings." - freak007
First part of the sentence you prove our point, and a 100 yard zero would be more reliable to build off of, and the last part is a bit concerning, you should always try to be as accurate as possible. The animal deserves it no?