I'm very sure that this is the case. Reddit is pissed they gave away all the content as training data for free while struggling to monetize their platform adequately.
But I suspect the damage is already done. There are projects like "Orca" from Microsoft that skip the learning process from source data for a big part by using chatGPT and GPT4.
They missed the timing but are too stubborn and double down on it
Was ihr Lappen.