I think that in about 50 years the toys will be worth nothing, because noone will know what the hell Macross was. People get into collecting products from a certain franchise first and foremost because they like the franchise. I think that, in 20 years time, the Macross franchise will be "dead", which means that no new toys/models/anime will be produced. Things like rare Batman comics are worth so much money partially because the franchise is so well known and alive since the early 40's.
Today there are so many franchises that Macross will just get snowed under by the bigger names.
BTW: I do hope I'm wrong though, and that in 50 years I'll be a millionaire because I imported Japanese toys that noone knew about in the early 2000's