You know I hear about this situation with so many of my PhD friends so if it's any comfort these supervisors are everywhere.
The way they cope is usually 2 - either bull doze their way through the PhD course themselves (really frustrating and they end up being really sad and burnt out by the end) or they find someone else to guide them..they never quit, either for pride or passion for the subject.

In my case, I'm facing the same damn problem too now 10mths into my PhD and I feel I'm teaching my supervisor more than he teaches me. I'm sending him papers, giving updates on like a fortnightly basis and you know what? He keeps asking me the same damn fundamental questions that make me feel like he has not been listening...so like you, he has a lack of interest in my field too...the cons of gg with someone just starting out in a field I guess. I feel like quitting too but I can't man! I have to pay my scholarship body like a quarter of a mill. if I quit wo a PhD so I'm taking things into my own hands and approaching the scientists in a research institute and tell them honestly that I'd like guidance in exchange for my hardwork...still finalising this so I'm not sure if this will work out too...lol I'm trying hard to keep myself sane!

I hope you can try this too.