most of the guards were at the archway.. but its not important

There were more at the Avatars, actually. By the end, at least.

Anyhoo point being, we make more power because there appears to be some expectation (which is being met) that we will spent more power to protect are more open, more easily raidable Communes.

I'd still prefer to have a very big gift of power and be expected to spend most of it on guards than not get any free power at all and not have guards. Cities seem worse off power gen wise than communes, I mean before glomdoring won the library stuff if they had the same power generation of cities they wouldn't have been able to have any significant ammout of guards anywhere.

Unless we had standing orders to harvest everything from the Plane of Shadows (our elemental plane!) constantly, with Commune favours for those who gathered large numbers / sand to keep the power generation from that high, and so on.

So assuming that we also didn't need to plaster the Plane of Shadows with guards, and Ethereal Glomdoring no longer existed... we'd be spending about 1500 power each weave on guards. 1000 from the Drums and 500 from culture (a bit less than our average, pre cultural center) covers that, and it's possible to make another 1-2k a weave from constant harvesting of an Elemental plane, especially with 4 sands imbued.

We don't have a direct connection to an Elemental plane, however, nor do we put a lot of effort into gathering sands / killing for essence. If we get a sand or two, great.

Well sand for celest and spikes for mag are the same as our crow shadows, but thats a lie I can name a combination of three or four people who actually have raked in more than 1000 power from essence and shadow gathering in a weave . Communes and cities have equal power gen exculding the 3k from totems. I mean ive seen chandestri over 300 on her own once thats like a villiage on her own. The elemental planes are kinda accessable for everyone so its not really a big advantage to the cities.

No, spectres are their equivalent to our crow shadows. And I can name a person who has brought in 1000 power in a weave from essence hunting when it was at two each- not a combination, but one person. With essence at 5, that's 2500 for ~12 hours of work. Four people at three hours each hits the same thing without being anywhere near as boring, and that's still only half the day.

While Communes can get essence from the Elemental planes, most of it goes to the cities. There are a number of Magnagorans who will ask you to hand over any essence you pick up (as well as corpses), and so on. I don't know if Celest does the same to Serenwilders, but it is possible to do.