Hi, Coltdriver,
I think the appeal is part of the current WWII fad, which included the silly "Saving Private Ryan" and other movies and TV shows of greater or less value. The M1 rifle, M1911A1 pistol, and M1 carbine are a part of the history of "the last good war" that can be owned by the average person, where other WWII weapons either are not practically available (no M4 tanks or F-51 fighters on the local used car lot) or are under the NFA.
The M1 was also the military rifle of people of my draftee generation who have evicted the kids and are now both nostalgic and well off enough to shell out some money to satisfy that nostalgia. (It is no coincidence that antique galleries play background music from the '50's and '60's.)
The real weapons are of historical interest; unfortunately a host of ridiculous laws and regulations have resulted in reproduction receivers of questionable quality and no real historical interest.
Jim