I didn't state that they were.
Hades is used as a "word", that could mean a temporary, however Gehenna isn't traditionally assumed to be in accordance with some timeline. The gehenna part is just 'destruction'. It doesn't mean it isn't a permanent state. There is some jewish 》 early christian reference to this. I'm not aware of a specific notation that hell/gehenna, isn't permanent.
Since 'emptied-out hell' is cast vacant into that symbolic ' second death ' of Revelation 20:13-14 then biblical hell is temporary. Since Jesus was only in biblical hell for a temporary amount of time, then if biblical hell was permanent then Jesus would still be the Bible's hell.
Everything thrown into a fireplace is gone forever. ( ashes Not put back together again ).
So, the fires of Gehenna ( garbage pit ) destroyed everything thrown into Gehenna.
So, that to me is why Psalms 92:7 can state that the wicked will be ' destroyed forever ' ( permanent destruction ).