I think the convenience of them isn't there yet. Pairing is a pain, charging, no ideal designs yet, they don't just work always.
People don't really care about sound quality.
I don't think people care about sound quality much either judging by how many people use the pack ins, but the £50 Bluetooth earbuds and headphones I've trialled last year sound worse than the iPhone pack ins which is going to be a deal breaker to some people.
Those Beats Solo wireless will probably change people since even the wired model has a battery. NFC pairing makes it easy, but they're still over £200 a pair.