http://www.4colorrebellion.com/archives/2006/06/13/mother-3-wii-fan-mockup/

Will Earthbound/Mother still resonate in the West like it did in Japan

Itoi made it very clear that he is done with Earthbound.  And for people who follow him, you'll know that videogame production was never his main aspiration in life.  It was more of a spontaneous side interest.  However, that being said, another game by Itoi, not necessarily in the Mother series, is more likely.  And I wouldn't mind such an offering.

I loved Earthbound like you guys did, but theres no reason for there to be a sequel just because you loved a game.  I like the movies American Beauty and Eyes Wide Shut, but why the hell should that merit a sequel???  The creative genius behind Earthbound was Itoi.  My main hope would be to see something different come from him so that his skills remain fresh and his creativity inspired.

Nintendo hates me, so I doubt they'll ever make a new Earthbound with an official Western release. If they did decide to make a console version for their next console, then that's going to be the first console I buy next generation.

Outside of Smash Bros appearances, I think it is safe to say, it will take another 5 years to a decade before we see another Mother/Earthbound RPG game.

Mother is somewhat big in Japan, very comparable to FE.  Famitsu numbers...

• Mother 1 plus 2 (GBA) 278,225
• Mother 1 plus 2 Value Edition (GBA) 110,300
• Mother 3 (GBA) 369,598

• Fire Emblem: Genealogy of the Holy War (SFC) 429,763
• Fire Emblem: Thracia 776 (SFC) 158,695 
• Fire Emblem: Sword of Spirits (GBA) 345,574
• Fire Emblem: The Blazing Blade (GBA) 265,286
• Fire Emblem: The Sacred Stones (GBA) 246,719
• Fire Emblem: Path of Radiance (GC) 156,413
• Fire Emblem: Radiant Dawn (Wii) 171,924
• Fire Emblem: Shadow Dragon (DS) 252,309
• Fire Emblem: Heroes of Light and Shadow (DS) 231,656

Thinking about it makes me sad even though I never actually played any of the games - people talk about it so fondly

I just love Lucas SOOO much in Brawl - I don't use anyone else anymore

I wish I could see something from the series someday

I've lost hope, but I wish it happened.

Actually, Earthbound (Mother 2) was a fairly big success in Japan:

Yeah, Mother 2 was the series highpoint and it shipped more than Mother 1 or any FE ever has.  Sadly though, we don't have any Famitsu sales figures from back then, only weird point rankings. :/