Well… by Western standards the patent on silk (tea is probably no even applicable) would have expired a couple of thousand year prior to the 1800s. Nobody is arguing in favor of perpetual patents..
Edit: the Romans first “stole” silk in the 500s, but still
What's the royalty on tea cultivation?
They also fought the Opium Wars over tea (well, trade imbalances resulting from the tea trade).
To be fair it’s not like the Chinese were unwilling to buy western goods (not just opium) it’s just that the ultra mercantilist Qing government didn’t allow them to..