That's exactly the reason, and it's transparent to the point of hilarity.
We also should factor, that a good chunk of the Steam sales are likely PS5/PC owners who chose the PC version due to factors like better performance potential (with high-power GPUs & CPUs for crazy frame rates) and free online play.
Safe to say at least 30% of the Steam sales are from that and WOM mainly being generated by PC/Steam (due to transparent CCU and player metrics data, most influencers/streamers being primarily PC as well).