Because the actual pairing wars out there are way too violent now for Kishimoto to take a choice.I bet that whoever he picks ups for Naruto,he actually may face people wanting his life.What's more it's a shounen and there are renown to lack romantic substance in them.
Bet he'll end up alone,probably by choice for whatever reason.
I'm pretty sure that he lives in too isolated a bubble to even be aware of pairing wars. I mean, popularity polls and sales and stuff are easy to see in nicely compiled reports that the magazine puts together anyway. But pairing wars take some effort to check out, and if you have a job you just don't have the time.
And checking out some of the pairing arguments is more annoying than interesting. There is nothing anyone has to say that is groundbreaking, and they always say the same thing. They
seem groundbreaking to the person typing it up so they easily end up becoming tl;dr arguments. So why would anybody want to pay attention? I mean, it seems that the only motive people have for participating is to defend a side.
So I really don't think all the blood and tears people put into pairing wars have any effect. It's even more annoying to come across a tumblr or forum post of somebody wanting to form petitions or pulling overnighters forming an argument for a pairing... as if the effort is a noble one U_U . It's annoying because I've come across a post or two where someone tried to take credit for events in the manga that happened in their favor.
SERIOUSLY!!!