It all comes down to the operator. CASA has outlined splay requirements in MOS139 including allowances for displaced thresholds to allow runways to remain open etc, however some operators are opposed to displacing runways for several reasons. If the operator can make the numbers work then CASA is happy, however displacing thresholds can be a pain in the ass and is a liability if its done wrong. One operator i know of that does not displace thresholds is Perth Airport who havent had a displaced threshold for years becasue of the
2008 Garuda and
2005 South African incidents where one landed on a closed section of runway and the other had several goes at doing the same. Even now, they close one of the two runways whenever there is runway works.