I dunno; maybe what the OP meant was that all $600 speakers have about equal SQ and all $5000 speakers have about equal SQ as well, and that using the term "the same" may have been an unfortunate use of the wrong words to get across what may have been an interesting comment.

For instance I'm listening to two sets of headphones, the forward and exciting Alessandro MS2i, and the laid-back and darker Sennheiser HD600, which sell for about the same price and sound a whole lot different from each other but both have about the same level of SQ. They both sound equally as good. The same goodness.

The hole in the theory is that ya still gotta listen to and test different speakers in each price range to determine just which sonic signature you prefer.