Wherever people work the soil and raise plants or domesticate livestock, the Earth Goddesses are revered. Some places, where the male ruling deities have unquestioned authority, they are little more than the local Grain Goddesses. In other lands, Ernalda is a power that must be acknowledged and women are revered for their magical potentials.
In most lands, the Earth Goddess is protected by a husband deity or deities – Yelm, Lodril, Orlanth, even Storm Bull or Argan Argar. As long as the husband deity protects Her, cares for Her, and respects Her rights and authority, the god rules in most other areas. For example, in Dragon Pass, the Feathered Horse Queen is co-ruler with her husband (to avoid having to rule with another, most Feathered Horse Queen take consorts rather than husbands).
But in a few areas, the Earth Goddess is the ruler. Esrolia is the best example of this – a survival (or restoration) of pre-Gods War practices. Ernalda THE Earth Goddess takes husbands who serve as protectors, but Ernalda remains the ruling deity.
Have there been instances of Aldryami coming into conflict with human Earth cults? In general, the Earth Priestesses and the Aldryrami are able to find common ground. The cults are associated and can work together. Pastoralists often come into conflict with the elves. The Praxians in particular used Oakfed to burn down the elf forests in Dragon Pass. Remember that the goddess of these crops is Aldrya’s mother.
I don’t think there is that much of a conflict between the Aldrya cult and the local Earth Goddess cult. Such conflicts are likely rare and driven by personalities rather than fundamental issues.
But I suspect there are often conflicts between Aldrya and the Husband-Protector, especially Lodril, Orlanth, and Argan Argar!
I find it useful to remember that the Earth Goddesses underlay almost every agricultural or pastoral human society. The Lightbringers, Solar, or Lunar deities might rule above the Earth, but the Earth is always there, feeding humankind, and bringing forth new life. These goddesses are the foundations upon which civilization can rise.
How about the social effects in Esrolia where Ernaldan queen’s rule? Esrolia is an Orlanthi culture that – during the height of the Great Darkness sought survival with the Earth Goddesses (with all the husbands dead).
Esrolian culture is largely egalitarian between the sexes, with the Earth Temples being the ruling temples (unlike in Sartar where the Orlanth temple is the ruling temple). Cults like Issaries, Orlanth, Lhankor Mhy, etc., govern themselves as normally would. However, the Earth Goddess does not appoint a single Husband-Protector, but acknowledges all of them, and then mediates between them.
So for an ordinary male farmer, this is not all that different from his kin in Sartar. The kinship group is headed by an Earth Priestess instead of a Big Man. But our farmer worships Barntar or Thunderer just like his Sartarite kin. The Thunderer temple is headed by a Storm Voice (usually male). The Lightbringers are all there, just as in Sartar – but the big difference is that the Earth Goddess reigns supreme as opposed to her husband. This is Her home after all!
Esrolia is the best example of an area ruled by an Earth Goddess. What about others, like Pelanda? Pelanda is not a matriarchy or Earth Goddess ruled land. It is ruled by the Yelm cult and by the Lunar deities now. There are echoes of the older Earth cults there, which are remembered by story and myth, but it hasn’t ruled itself in over an age.