You know, people are always shocked by how much my dance dresses cost--but I've worn my Smooth gown six times and my Rhythm (which is newer) at least three times so far. I have a $185 bridesmaid's dress in my closet that, let's face it, even though it's nice I'll probably never wear it again because it looks like a freakin' bridesmaid's dress! Ultimately, which dress costs more in terms of hours worn vs. price? Let's not even get into what your average wedding gown costs these days (in the unlikely event I get married I am refusing to spend more than $1000 on a gown because really, WHY? BTW, my divorced friend would like to know if anyone wants a wedding gown, slightly used. You think dance dresses are hard to resell....)
Regarding the whole dance-as-prelude-to-romance thing, I've never really gotten that seriously, just the usual "are your teachers straight" and "are they hot?" Possibly because I don't do much social dance and don't have an am partner.
"It's not a sport": Yeah, I've heard that about figure skating and horseback riding, too. (In the former, same as dance, it's too "pretty" to be a sport, in the latter case "Doesn't the horse do all the work?") I've learned to just let it go.