Yeah, that's more what I meant; it may not be literally every girl who's getting a boyfriend. And, c'mon, you've gotta admit, arguing that falls a bit flat when a) the number you cite of girls you don't have OCs for is substantially lower than the number of OCs you've cited, and b) you admit that most of those are characters you're just not interested in to begin with. It's more like "Why does every girl you want to focus on need to be in a relationship?"
But that is my perspective as someone who's generally not into shipping in general. I find most romances pretty boring -- and the ones I do like, I find, are ones I can see as natural outgrowths of the characters' pre-existing interactions. So pairing characters off for the sake of pairing characters off is rather unappealing to me. (Actually, as far as Touhou goes, the fact that there's absolutely nothing I ship* is a little unusual, especially since I usually lean towards yuri. The whole series just seems so asexual to me, and unromantic too, and I'd hate to muck that up.)
But I realize that that's... ahem. Not everyone's feeling, to say the least, in this fandom or any other. Besides, it's not like merely having romance makes a story automatically bad (although my preferences mean that poorly done romance turns me off lightning quick). 'Scool.
* Technically, there are a couple pairings that I like, but I don't consider myself to ship them; they're nice, but at the end of the day I'm still happier with the whole world being platonic.