Browning himself went to the external extractor several years later, with the High Power. Modern pistols such as Glock, HK, etc use external extractors with uber reliability.
The GP-35 was actually finished after JMB's death by FN enginer Dieudonne Saive, and it originally had an internal extractor.
Things change over time. Improvement do designs take place, and are implemented.
Could the external extractor actually be an improvement, but purists do not want to sway from the original design?
Could it be? Yes. Has it been? No. As I noted above, industry giants Kimber & SIG-Sauer have tried the EE on 1911s, and failed: The jury is still out on the S&W EE on their SW1911.
So if you don't consider the S&W a 1911 because of one part (extractor), how can you consider a 38 super which has mulitple different parts a 1911??
Simple. Those different parts only change caliber, not mechanical function. The external extractor is actually a minimum of three parts (extractor, extractor spring, and extractor retaining pin), and requires milling out part of the exterior of the slide. The EE changes how the gun functions. See my Glock example below.
of course! There is nothing wrong with being a purist though, it would just be nice if they would admit that is their motivation, and not claim that internal extractors are inherently better somehow.
No company has yet executed an EE that performs better than an IE on the 1911. Even if the EEs are made to function just as well as IEs, they still require specialized tools to service, and add to the parts count of the gun. The internal extractor has some serious advantages, namely field expedient cleaning & replacement.
some that don't consider an EE 1911 a 1911 is because they don't want to...well...where do you draw the line???...front cocking serrations???...front strap checkering???...short trigger???...double stack magazine???...undercut trigger guard???...flared and lowered ejection port???...magwell???...different magazine designs???...different sights???...ambi-safety???...beavertail or duckbill grip safety???...different calibers???...hmmmm??
Does the part change the mechanical function of the weapon, or is it a cosmetic change?
If I take a Glock 21, and put in a Glock 20 bbl, extractor, and magazine do I still have a Glock? If I put an aftermarket .400 CorBon bbl in a Glock 21 do I still have a Glock? If I manufacture a slide with an internal extractor, no striker block, and a 9x23 Win bbl that functions on a Glock 35 frame, and put it on a Glock 35, do I still have a Glock? If I put that hypothetical slide on a CCF Glock Raceframe do I have a Glock?