I’m sure this has been discussed elsewhere, as I’ve been sitting on it for a few weeks now, but I think there are some worthwhile things to discuss here.
My first thought was that this recent largeish drop might simply be an effect of Covid. But even if it is connected, it seems likely to simply have sped up an ongoing change. In other words, it is likely to be a permanent change, given the rise in number of people who have “no religious preference,” not a temporary blip because of temporarily closed churches.
The article does hit on some sub-points, such as the generational differences—the drop among the younger generations is particularly brutal and sad—and the fact that Roman Catholic membership is particularly hard hit, compared to Protestant.