I don't think Khan really loses any stock by losing to Floyd, unless he gets absolutely humiliated, which I don't see happening. Mayweather shut-out Canelo but Canelo has headlined two PPVs since. I think there are a lot of interesting fights for Brook at 147. But he has to travel to the US for them, something which Hearn isn't willing for him to do, cause he'd be unable to put it on UK PPV. Unless he gets the Khan fight, Hearn's PPV motives will continue to hold back Brook. Khan and Haymon know this, which is why Haymon won't send any of his fighters to the UK to fight Brook. And Haymon pretty much owns the welterweight division.
Wrt Price, I watched his last fight and he looked absolutely horrible. Shot of all confidence.