Are you trolling? It clearly says: "Firmware 5.5x: fully exploited in private."
I believe there is an exploit they have been using on multiple firmwares to be able to dump the kernel & then they start looking for exploits that Sony have fixed in the next firmware.
So there is often an exploit pretty much straight away, but there is no way that is going to get released. If they did, then we'd probably be waiting even longer between releases.
It is likely they will look for fixed exploits in 6.0 before releasing one for 5.50 & that obviously can't happen until 6.0 has been released.