Most have had the engine changed well before the PCV go's bad
The rubber has gotten hard over the years and won't give up the PCV valve
with out some serious KY Jelly. Lol...
Soak it with that PB Blaster or WD 40 several times and let it try to make
that rubber plyable again. Keep working it till it comes out. When putting the
new one in use lots of grease and be carefull not to push too hard and drop
the rubber down in the intake.
It'll come out.. she's just stubborn!