My question is how could this have been an issue for over a hundred years?
The good news is it wasn't an issue for over a hundred years. I'm not a firearms historian so those who are may rightfully nit-pick what I'm about to say.
The 1911 was designed to meet the military requirement that all parts be interchangeable between pistols without the need for additional fitting. This requirement was frequently tested throughout the production phase by obtaining random samples of all the parts, tossing them into a barrel, then assembling however many pistols worth of parts were in the barrel. Every pistol had to function and pass all safety tests.
In order to achieve this feat of mass production, each part had to meet the blueprint specs. Every company that made 1911s (e.g. Singer, Rand, Colt, etc) used the exact same blueprints.
Fast forward to today. Everyone and his brother makes 1911s and none of them use the same blueprints or have the same stringent quality control demanded by the military back in the day. What you end up with are different dimensions depending on who does the manufacturing. So, one manufacturer's slide may well have a different distance from the firing pin stop slot to the breechface than any other manufacturer's slide. This alone would cause problems with finding the correct length extractor.
If there were only a single company that manufactured 1911s and used the original Ordnance approved blueprints, these dimensional problems wouldn't exist. Only Glock makes Glocks, only Smith & Wesson makes Smith & Wessons, only SIG make SIGs, etc. They don't have these problems (unless their QC is bad).
If you look at the drawings available on the internet then the claw must contact the round even on paper.
There is some debate on this which revolves around the issue of using mid-spec dimensions, tolerance stacking, and whether such drawings are from the actual Ordnance blueprints. I don't have a dog in this fight so cannot comment meaningfully.
However, I will say that a 1911 .45 ACP extractor claw works best when it does not touch the case anywhere. Further, the only contact between the case and the extractor should be at the case rim and the tensioning wall.
Since we know that manufacturing dimensions are all over the place, the axiom is that there is no such thing as a drop-in 1911 part. Nearly every part has to be massaged in some way in order to get it to work perfectly with all the other parts. The degree to which a part has to be modified depends on who manufactured which part and when.
It's very rare that an extractor can be used out-of-the-box without getting some attention especially if you're looking for perfect functioning. You may get lucky and find one that drops in and the pistol functions fine but that usually happens when the manufacturer made both the slide and the extractor (e.g. Wilson, Caspian). Once you get an extractor properly fitted, it will last a very long time without any problems at all. We're talking about tens of thousands of rounds. Basically, when the barrel needs to be replaced because it has become a smooth bore, replace the extractor.
Anyway, that's the joy of 1911s. You get to tweak these things to your heart's content to get them to work the way you want them to work. Glocks are no fun - they run right out of the box.
