Last I looked into it, the tire companies were looking at making rubber from dandelions, somehow. Seemed like it would be great if it actually became viable.
Dandelion rubber was totally a viable thing in Soviet Russia, or, rather, Soviet Kazakhstan. Like many technologies, it's not a question of feasibility but of economic competitiveness.
> TKS was cultivated on a large scale in the Soviet Union during World War II. The Soviet Union cultivated Taraxacum kok-saghyz, together with Taraxacum hybernum and Scorzonera tau-saghyz, on a large scale between 1931 and 1950—notably during World War II—as an emergency source of rubber when supplies of rubber from Hevea brasiliensis in Southeast Asia were threatened. The United States, the UK, Germany, Sweden and Spain also cultivated the plant for the same reason. During this time period, the highest yields achieved by the U.S. reached 110 kg of rubber per hectare, while the USSR achieved yields of 200 kg of rubber per hectare. The Raisko sub-camp of Auschwitz was a German-operated production factory for the plant. Some of the women deported on the Convoi des 31000 worked on its production there.[8] With the conclusion of World War II and the return of affordable Hevea brasiliensis rubber (which has 8 to 10 times the yield[9]), the majority of T. kok-saghyz programs ceased.
https://en.wikipedia.org/wiki/Taraxacum_kok-saghyz
> TKS was cultivated on a large scale in the Soviet Union during World War II. The Soviet Union cultivated Taraxacum kok-saghyz, together with Taraxacum hybernum and Scorzonera tau-saghyz, on a large scale between 1931 and 1950—notably during World War II—as an emergency source of rubber when supplies of rubber from Hevea brasiliensis in Southeast Asia were threatened. The United States, the UK, Germany, Sweden and Spain also cultivated the plant for the same reason. During this time period, the highest yields achieved by the U.S. reached 110 kg of rubber per hectare, while the USSR achieved yields of 200 kg of rubber per hectare. The Raisko sub-camp of Auschwitz was a German-operated production factory for the plant. Some of the women deported on the Convoi des 31000 worked on its production there.[8] With the conclusion of World War II and the return of affordable Hevea brasiliensis rubber (which has 8 to 10 times the yield[9]), the majority of T. kok-saghyz programs ceased.