

They did, to some degree. But usually new players are better at capitalizing on emerging technologies. Kodak did invest in digital photography, and Nokia in smartphones, to give some examples.
Shell had a solar division which they sold in 2006. (It has since taken some stakes in solar and wind projects.)



To be fair, for most of the applications of oil it’s not so much that it “relies” on oil, just that it’s the cheaper method (for now).
You can make a plastic bag starting from water and carbon dioxide (or some other source of carbon), plus electricity.