To gain synthetic rubber you need synthetic refineries, however historically synthetic rubber surely could be created from other raw materials.
Other countries developed synthetic alternatives to rubber; the USSR and USA. In Russia as early as 1910. There is of course the 'miracle of nature' focus which actually represents industrial processing as much as growing alternative crops that can be used as a source of raw material. But if coal processed into oil substitute can be used as a source material for synthetic rubber (polymers with properties similar to rubber) then surely oil can be used as source material for similar polymers. The USSR and USA have oil and no need to develop substitute fuel, bug they do need to develop polymers. Maybe I'm missing something, but I don't see this reflected in the oil and rubber tech tree.
Other countries developed synthetic alternatives to rubber; the USSR and USA. In Russia as early as 1910. There is of course the 'miracle of nature' focus which actually represents industrial processing as much as growing alternative crops that can be used as a source of raw material. But if coal processed into oil substitute can be used as a source material for synthetic rubber (polymers with properties similar to rubber) then surely oil can be used as source material for similar polymers. The USSR and USA have oil and no need to develop substitute fuel, bug they do need to develop polymers. Maybe I'm missing something, but I don't see this reflected in the oil and rubber tech tree.