U.S. destroyed TRON in 80'
by the trade war between U.S. and Japan.
Because, U.S. had changed the strategy anti-patent to pro-patent in 70', when U.S. was very afraid of electronicses and technic powers of Japan and German.
On the time, Japan gives birth of TRON.
Then, U.S. kills TRON for U.S.'s benefits.