Webley, +1. Another important consideration is that IMO they were losing the war by 1942 and esp by 1943. The failure of Battle for Britain was a warning sign that the Wehrmacht was not as mighty as it once thought. Arms became progressively harder for the Nazi's to make.
Grant - well its like this. You can buy a glock 19 and shoot the snot out of it, and then you can buy a luger. You're buying collector pieces (you need to sell me that SS PP ASAP, btw) and your luger, is probably a collectors piece (I'm assuming all matching sans mag with over 80% original finish and no import marking?). My attitude about this subject is this - why take the chance? Of course, like James K said, they're not brittle, but there is that possibility. It would be one thing if it were possible AND the parts were not serial numbered. Then it would be like shooting a pre war S&W and somehow the hammer broke or what you have you (very unlikely). The hammer could be hard to find, but at least its not numbered to the gun. With the luger, most parts are numbered. So you have two issues, finding a replacement part, and then actually finding one with the correct number and or proofmark otherwise the luger gains the mismatch stigma. Very hard if not impossible to get a matching part with proper proof.
I say why take the chance, because I bought my lugers as collectibles and investments. Other people say "hey, you only live once, lugers are great, a piece of history, and I can't have guns I don't shoot" and that's fine, but I would rather take no chances. If your gun is refinished, or does not match, then that is a different story. Some of my lugers are fairly valuable IE my Dutch contract, so I think some of the people who insist on shooting don't really own such a luger anyways. It also depends on how wealthy someone is. I'm not wealthy enough to disregard the current value of my lugers, other people may not care as much. I bought them as investments, not truly as "guns" but I happen to find guns beat out most other types of investments.
JMHO and YMMV