How much were these forums costing them? They don't actually employ people to answer questions do they? I thought it was more of a prestige thing to be an expert that answers questions on there. Even so, it probably costs less to run than any of their other existing support channels.

I would think that the reason is probably more to do with the changed landscape of online forums, ie. moderation in the age of LLMs is just too difficult, on top of the regulatory environment that's expecting age verification for anything with even a whiff of user interaction.