I think folks are approaching this in different directions, based on their definition of "value"... a word that only really has whatever meaning is given to it in context. If the OP means "monetary" value, then the statement is absolutely correct. Will a third party move in and force the buyer to pay some arbitrary sum, having decreed that somehow their subjective definition of "beauty" has been met (say, hanging elephant dung from the ceiling for a hefty subsidy)? If not, then it really is what the buyer is willing to pay, provided the seller is also willing.
Personal and emotional value is something else entirely, and not even in the same ballpark. I think there's a lot of unnecessary argument over a word that can be defined so many ways depending on context.
I have photos of my family that I value highly, but they're not "worth" any more than anyone is willing to pay.
Doesn't bother me a bit, because in the end, they belong to me.