I would say that's false, people are definitely into the league scene in the valley. living in Scottsdale, you are close to a lot of prime spots to network and meet people. can't really say that I have a lot of experience around 3.0 women, but my mom and aunt both play 3.5 tennis down in the valley on USTA teams. I want to say they had like 7 teams per session this last year, maybe 8 (I was also told that it was a low registration year, so could be higher this year!), in the 3.5 women. for 3.0 I have no idea but im sure there's at least a league going on, not sure how many teams are in it.
what skill level is your husband? i play in the 4.0 leagues down in the valley area and pretty much same story, 7-8 other teams, somewhere in there.
there are two sessions for adult league play in the phoenix area, fall/winter and spring/summer. generally (depending on total number of entrants in the league) the top two teams from each league play at the end of the year playoffs to see who wins that and can go to sectionals. if one or more teams finish top two in BOTH sessions, a wild card berth is usually granted to the end of the year divisonal playoffs.
league play is pretty fun but after sectionals of this year i'm honestly considering quitting the whole league thing and just sticking to playing with people I know and tournaments whenever I have free weekends
p.s. - check out the ATA, it's another league within your area. it's doubles only, but it's a weekend league and it's been growing in size the last few years now. also make sure you check out the monthly/weekly happenings at phoenix tennis center, as they occasionally hold one day, weekend tournaments.