Only because we use a lot of pine wood with low density (because cheap&fast). Not all wood is like that: Red cedar, douglas, larch, acacia and more... Where I live, chestnut is even used for roof tiling.
I've started seeing screw-tops as an accessibility feature after the last time I got a bottle with a cork that was impossible for my mother to open and ended up crumbling anyway. I'm done with corks forever; they just don't make sense.
Wood is useless for sterile applications because it harbors bacteria and such. Think dentist, doctor, chemistry labs, industrial processes, food manufacturing and packaging, chemical storage, etc etc. All Plastic.