Disagree. CRPGs back then had been hitting a minor renessaince for a while, notably from Owlcat, and D&D in specific has been on a never ending gravy train of popularity thanks to podcasts like Critical Role (and in spite of WOTCs attempts to break that gravy train by making inane audience alienating decisions).

BG3 whilst undeniably a massive success was likely always going to perform very well for Larian. The suprise was mostly that it ended up being a GOTY title I think.