Here's my synthesized version, combining Baryonyx with other information, and extrapolating some additional gap-fillers.
All power and potential in existence is linked to a source, called "The Source." One of the earliest, if not the earliest beings in the universe called the Primordials decided to control and shepherd how that power flowed to all other sentient beings by creating gateways to that power that sat between different species and the raw source. They selected beings that they transformed into wellsprings of power connected to the source, called "Wells." These Wells would each be attuned to a different species in the cosmos. Because each Well becomes connected to a species, it begins to reflect the potential and character of that species as it also empowers them to achieve their destined potential. This feedback is potentially dangerous and unpredictable so each Well was assigned a representative to act as its guardian and guide from among the Dimensionless, the representatives and foot soldiers of the Primordials.
The problem is that everyone has their own agendas. The Primordials seem to want some level of control over the Source. They don't care too much if other beings gain incarnate power, they just want to control the gateways to that power, thus their creation of the Wells. Apparently only actual beings can act as conduits to the Source (probably it requires having some sort of connection to the source in the first place to become a well, so it cannot be simply a device of some kind) so the Primordials sort of "ascended" them into becoming wells. But they still have some remnant of their original consciousness or will, if not all of it, and so the Wells themselves can have their own agenda as to how they provide power to their assigned beings. This is further muddied by the wells being influenced by their assigned species in a kind of symbiosis.
I get the sense that Prometheus was once the guardian of a different well, one where the beings of that world eventually gained so much incarnate power they became the Greco-Roman gods and discarded Prometheus as being of no further use. So now Prometheus is more wary of allowing humans to gain too much power too quickly, lest they become as arrogant and disrespectful. I also get the sense that our Well could care less: its actually fearful of the Battalion, knowing so many Wells have fallen so far and knowing it is next on the Battalion's hit list, our Well is trying to build the most powerful army it can to repel the Battalion. So much so it was willing to invest a large amount of power in Emperor Cole knowing he would continuously reinvest that power in building an ever stronger army, which our Well hoped would be able to repel the Battalion from Primal Earth.
For those who haven't put this all together, Rularuu is actually a more-or-less Ascended being that was once a different dimension's version of our Dream Doctor. He eventually grew powerful enough to destroy his own dimension and consume its power. He could then travel to other dimensions with other versions of himself, combine with that person, use him to consume that dimension, and then move on. By doing this repeatedly he amassed so much power he was able to Ascend to a higher form. What temporarily stopped him was our Dream Doctor, who was able to foresee his coming and repel him from our dimension. It is this event that causes the Battalion to both take an interest in Earth, and also be wary of it as they do not know how we were able to repel such a being.
Given all that, I can see a way to avoid certain otherwise intractable problems with the backstory. For example, if the Battalion has consumed hundreds if not thousands of wells, how can we hope to fight them? Answer: Wells are not the source of power, they are only gateways to the Source. By consuming them the Battalion has taken some of that power, but it has also closed doors to the Source. With each well they close, they could be making the remaining wells brighter. In other words, all the while the Battalion has been growing stronger, they may have been inadvertently making the remaining wells, like Primal Earth's Well, even stronger. We might ironically have never had the levels of incarnate power we had, so quickly, and so pervasively on Earth if it wasn't for the Battalion concentrating the Source into fewer and fewer Wells.
So why are the True Rikti so (implied) powerful? Because they are one of the older races in the galaxy, and they gained their power at a time when there were fewer Wells. Fewer Wells, more powerful Wells. They achieved their full potential at a time when very few beings were competing for the Source. Their Well is bigger and brighter, which is another way of saying their connection to the Source is stronger and more powerful, as a result. That's what makes them so dangerous: the older the race, the quicker they achieved their potential, the more powerful that race is likely to be.
And if the Battalion is making Primal Earth's well a little stronger as they consume other species, think of what they are doing to the True Rikti. Which is why the True Rikti aren't trying to knock them off first. They are letting the Battalion take care of the little fish, then they will swoop in and take out the few remaining big fish, and they will then end up with an *enormous* amount of power.
And most of the Dimensionless aren't really stepping in either, because even the True Rikti's plans aren't a direct threat to the Primordial's plans. The only true threat to the Dimensionless and their Primordial masters would be Ascendeds like Rularuu and potentially Hamidon, who have somehow bypassed the game entirely and have the potential to connect directly with the Source, bringing them into parity with the Primordials. They don't care who wants to be the top dog standing on the Incarnate/Wellspring molehill. Anyone playing the Incarnate/Well game, even playing it to win by taking out all their competition, is playing the Primordial's game. Rularuu and Hamidon aren't playing that game.
