The room is possible because there's someone inside with a big list of rules of what Chinese characters to reply with. This represents the huge amount of data processing and statistical power. When the thought expt was created, you could argue that the room was impossible, so the experiment was meaningless. But that's no longer the case.
if you go and s/Chinese Room/LLM against any of the counter arguments to the thought experiment how many of them does it invalidate?