Using a substitution solver for monoalphabetic ciphers, we get this:
The final cieme, the very last key everyone was looking for was never found and so the cuzzle bemaje unsolvable. Within those who mhallenged it, those few first, was no longer a need for michers. Those who mhallenged it were the first to realize that there was no word that mould be used to demicher:
Uao srtzqdb mzdqdb dpeudf euc euelaon compol poxdstdc
Obviously, this isn't perfect, but readable, so the actual probably says:
The final piece, the very last key everyone was looking for was never found and so the puzzle became unsolvable. Within those who challenged it, those few first, was no longer a need for ciphers. Those who challenged it were the first to realize that there was no word that could be used to decipher:
Since we don't have the full alphabet used in the above paragraph, we can make only educated guesses as to what that last line becomes...
Uao srtzqdb czdqdb dpeudf eup euelaon pocpol poxdstdp