Because there's no other material with the same properties, at least one that can be made cheap enough and won't fall apart by itself. It's just like oil and gas, we use it because we don't know anything better.
The only way to replace plastic is work hard on making different materials that beat it in every way and scale them up with massive state investment. Then you're fighting multinational companies, neoliberal economists, anti tech green activists, skeptical scientists and corrupt politicians all at the same time.
The only way to replace plastic is work hard on making different materials that beat it in every way and scale them up with massive state investment. Then you're fighting multinational companies, neoliberal economists, anti tech green activists, skeptical scientists and corrupt politicians all at the same time.