They do rival wired headphones at the same and similar pricing. Why should a $400 wireless rival say a $2000 wired headphone? They aren't even really designed for the same type of listening. I don't think people buy $400 wireless for pure, critical listening, they buy it to have high quality sound wireless. And yes, we will see this equivalence soon as you say, but the prices will also become equivalent so the top of the line Bluetooth headphone will start costing as much as any wired flagship.
I think when you look at how people use a Bluetooth headphone, at least based on my sense and experience, they aren't trying to find reference grade sound, they know there will be some compromises. A great deal of the sound signature comes not just from the driver, but how they are tuned to work with the enclosure and obviously non-portable headphones that don't need to have a battery and electronics in the cups have an advantage tuning wise. Not to mention, portables are generally smaller and lighter so a Bluetooth headphone is already at some disadvantage. That said, the sound signatures achieved with Bluetooth can be excellent and some may even prefer them, or at least really, really like them.
I'm not disagreeing with you completely, I'm just saying that in my view a true portable Bluetooth headphone doesn't have to equal or compete with stay at home, full sized headphones.