With the exception of Battlefield: vietnam, is there a reason why mainstream War FPS franchises (especially COD series) has left out Vietnam?  I think it is safe to say almost every conspiracy/campaign from WW2 has been covered and modern warfare has been successfully coverred, but I'm left craving a little vietnam action.  Even Korea would be a nice change of pace.  Are there any War FPS genre games that cover Vietnam or Korea and are worth a play that I don't know about?  Is there a reason why these 2 aren't touched in the mainstream market (BF:V aside)?

I could be wrong but, I think there is a game by The History Channel that is Vietnam based. I'm not real sure. Other than that, I can't think of one.

there were few war games last gen based on Vietnam, those games bombed.

Isn't there a game called vietcong (or something along those lines)?

Also, I'm going to say that, in the market where most FPS/War FPS thrive (America), a game depicting their worst military decision (what I've heard, I wouldn't know personally, I don't look up the histories of countries I have no interest in)
doesn't sound like a game that'd go down to well.

There is a "ShellShock Nam´67" game for the PS2. Didn´t like it very much. Didn´t finish, though I think it´s because I had other games to play and I ended up forgetting about it.

I think that too many americans are still shocked by what happened in vietnam.