Just like gas as energy for transport, plastics are difficult to replace. Their main advantage is that they can package food and greatly improve their conservation and transport. This is also true for medical supplies.
A potential solution would be to use standardized glass packaging, and encourage consumers to return them and reimburse them, but it would be complex logistics, and it would be heavier to transport. It would also mean a change of shape for food packaging.
Even metal is not a perfect solution, since metal also has a plastic layer inside. To be honest, even the lid of glass bottles has a layer of plastic, too.