As someone has already stated, they recycle these notes as well. Even though they're plastic, they won't last forever. It doesn't help they're high denomination

As someone has already stated, they recycle these notes as well. Even though they're plastic, they won't last forever. It doesn't help they're high denomination and therefore less used, but I wouldn't be surprised that after about 50 years, there will be a lot less of these. They'll be even more rare in an un-circulated state.