WHY DQ isn't popular in America

Hello!Nice to meet you.
I'm a Japanese.
Well...I have a question.
Why the Dragonquest (In America it called DragonWarrior) isn't popular in America?
DragonQuest is most popular RPG in Japan (than finalfantasy).
It's wonder for me.
WHY?
Could you tell me your thinking(opinion?)about it?

Sorry,Poor English.

One of the reasons I dont like DQ as much as FF is because they all seem the same.

DQ 1-4 all the same gameplay. I want new things. Change magic system, change battle system.

FF1 and FF2 are so different, then FF3 uses job system, something new and exciting!
FF6 so very new and different, espers and learning magic for everyone is so unique.
FF7 has materia and FF8 uses junction, FF9 learn through equipment.
FF10 has sphere grid, so different from 1-9.

DQ has same thing for every game, gets boring.

I still like it though, I play and have fun. Better than Breath of Fire.