I call bullshit. China's software industry boomed when they blocked/hobbled western big tech companies that would have strangled them. Slater kicked of America's textile industrialization. Every country that I know that has implemented a quota system in the arts has resulted in the domestic industry blossoming and getting over the self-sustaining hump.
It is self-evident that limiting competition is beneficial to the protected parties.
It is self-evident that limiting competition is beneficial to the protected parties.