Yeah, I saw that thread, which got me thinking about my own neck of the woods.
HeatSync is even more remote than Mesa/Tempe, being in Chandler.
I've usually tried to organize groups that are reasonable central or accessible to most folks in the Valley, but it's a very hard thing to do, and, as with HeatSync, people often just decide to serve their immediate vicinity for their own convenience.. (Which, unfortunately, becomes reinforcing overtime.)
I'm not unyielding on the finding or starting an Arduino hacker group that's not in Scottsdale, though it's my first preference. If anyone has a good suggestion for a location that isn't way off in the boondocks I'd be interested.