With the amount of trash in the ocean, I wouldn't be surprised if even an uncontacted tribe is running around in mismatched sandals and drinking out of old plastic bottles.

A guy I watch on YT has done a couple of short shipwreck survival challenges on some of the little islands off the coast of Australia. He starts barefoot and with no supplies and within an hour of scavenging the beach he has a pair of sandals, a half dozen bottles, both plastic and glass, and usually some fishing line or rope.