Huh
Good point
The whole book (movie) was about symbolism
The "yellow brick road" led to the gold standard which the writer portrayed as a fallacy with nothing but a false idol and a man behind a curtain
The author was against the gold standard and most likely in favor of the ultimate alternative
The red brick road would then be the obvious symbol for communism which would be the alternative to a free market and gold backed currency
There are only 2 roads