That might explain Virginia (and I think it is not that simple), but in any
> case it wouldn't help with Massachusetts or Connecticut.
>
Nothing ever is, but I think that's generally acknowledged to have been the primary factor.
The only state to have disestablished its Congregational church around the same time as the five Anglican states disestablished theirs (1776-1790) was New Hampshire (1790); I don't know what was going on there, although others might. I think it would be a mistake, though, to assume that the disestablishments in Connecticut (1818) or Massachusetts (1833) were necessarily part of the same historical trend, although they may have shared some common factors.
-- "Hige sceal þe heardra, heorte þe cenre, mod sceal þe mare, þe ure mægen lytlað."