It's not a total waste, since poly will eventually wear out/cold form, and deteriorate from heat-cold cycles, whereas the alloy ones will not.
But if they truly are poly, one could wait until the above happens to them before replacement.
I have a 2016, built in early September 2016, and it definitely had the very soft rubber/EPDM (maybe even a silicone-like material??) type bushings in the under hood shift cable bracket.