I agree totally with the assessment of what the factory engineers are up against. The 1911 however, is a special beast. The original intent was a combat pistol that every soldier could be easily taught to use. It was not meant to be a target pistol. Combat accuracy is not the same as what a target shooter would want. The military also needed something that had standardized replacement parts. Any good civilian AR will shoot tighter groups than a mil spec M16. The one constant I have heard and read over the last 40 odd years is the tighter the 1911 the less reliable it becomes when speaking of the original design. Unreliable is not acceptable for a combat/defense handgun while 5 inch groups at 30 yards is. It's a matter of what do you need it to do. I don't own a 1911 at this point not because I don't like or want them, just don't own one now. I have a Para 14.45 which is a fine piece. I also own a Firestar in .45 which I feel is an improvement over the officer's model 1911.
after all of that, I also look at modified guns like modded cars, I'm not paying extra because I don't know what is in there. It could have top quality parts installed properly or crap thrown in wrong. I trust my own judgement and "gut" when buying. If I make modifications, they are for my own taste and wouldn't expect you to pay above retail for used parts. My tastes are not yours but if the asthetic mods agree with you then why not? I polished a stainless 357 several years ago because I liked it, an aquaintance saw it and had to trade me out of it. yes, I made a bit on that deal. Maybe "Bubba" actually knows what he is doing. I am not a gunsmith but I do know how to polish a feed ramp or sear correctly. Do you trust that? Maybe you should but if you don't I fully understand, we don't know each other and my trust for you is in the same range.
for TLDR - buyer beware as there are no absolutes.