Because most Americans started with Wing, which (for whatever reason) turned out to be a brilliant synergy between timing and executive choice. I think we almost got X or Turn A first, and I don't know what that timeline looks like.

MSG remains a masterpiece and a watershed and all of that, but it is possible to choose a Gundam series that incorporates many of its objective strengths without the aspects that can be hard for newcomers to approach. (But whichever one that happens to be depends on who you ask.)

G Gundam might've been the most uncomplicated, yet wrong, series to introduce the American mass market to the franchise.