You are in the midst of an "ancient" argument
For years those of us in scale modeling asked the same basic questions. Why is it that the "dark side" is more appealing? Specifically, German stuff just seems to excite many people. The engineering was interesting and quite different than many Allied approaches. They often applied good tactical sense to the production of weapon systems. The German tanks have either a 1930s throw back look (Pz IV and earlier) or they have an angular "bad guy" look. The Germans embraced various camouf;age painting schemes early in the war, the Allies were rarely so colorful. I fully sympathize with your attitudes and some of the complaints. I am a notorius "GI freak" and I buy much more US stuff than German, but I will admit that on a lower shelf in my display case is a small K&C German battle group that were bought just 'cause they look cool.
The German vs Allied argument has been running thru models and toy soldiers "forever". It MIGHT be hopeful to realize after years of waiting the Allied stuff has become more prolific and of much higher quality. Glance through the new and upcoming vehicles on Terry Ashley's Perth Military Modeling Society (PMMS) web site. His site is the best place to get updates on the 1/35th market and you will see that quite a few of your requests have come out in plastic. Some of our "collectible miniatures" manufacturers use plastic models to support development of new projects, so more and better models can translate into more new Allied projects - it will just take time.
On the other side we still buy products from naufacturers who are just LAZY in their research in Allied subects. Two specifics are the K 'n C "DDay Sherman" which not nearly what it claims to be, and Collector's Showcase putting out that M4A1 with the glaring error on the rear. We still have a LOT of people who buy an item because of the name on the box, or because it's "good enough". Until we demand that these guys produce decent products I don't see them moving into some of the other stuff you want. Why make rare models when the collectors will buy any old crap? Just appreciate the releases that come out and that are correct models and don't buy the junk - vote with your hard-earned dollars (or Euros or whatever).
Gary B.