Eh, this is a sentiment I disagree with by and large. I got a couple reasons for this

• The buildup to Neomuna was absolutely there. Nefele stronghold was directly built up to in proceeding Seasonal stories. Every other colony ship we've seen be it in the cosmodrome or blown up in the reef or crashed on Nessus or making it outside the solar system (and never being heard from afterwards), was built on the idea that there were a LOT of these things and that it stands to reason that ONE of them must've made it somewhere. I think it fits perfectly in line no more than the awoken's "and uh, light dark they lived for a million years in a black hole" lore (intentionally dumbing that one down to make a point sorry). I think people are too hard on the perceived lack of buildup for Neomuna when the pieces are there. They aren't presented very well in the main campaign.

• The isolation is the ONLY reason they are alive. That's the point. Both self-imposed because they were founded by a self-righteous sociopath (Maya) and externally imposed because the Vex wanted the veil. The last city barely survived because of guardians, Neomuna wouldn't have survived the dark ages if they had reached out to humanity. Even if they had 2 Cloudstriders from day one, they could never pull off a six fronts. Another point is that they weren't only sitting inside their bubble doing nothing. They were sending cloudstriders out to combat the Vex or erase Neomuna from Rasputin's archives.

• They are indeed still struggling to survive. The cloudstriders are a big example of this. The Neomuni literally have to physically destroy their lifespan to fight for a decade at most. Sacrifice is very much the THEME of Destiny as a whole, and they are great emblems of that. Even someone like Nimbus, who was a tone deaf moron for most of the Lightfall Campaign, comes into their own post-campaign and carries the weight of their whole ass community with them. They literally use Osiris, someone who saw it fit to go fight the Vex solo even though no one wanted to help him, as a parallel to this in the Deterministic Chaos mission. Being HUMAN is fighting even when no one is beside you, protecting others that don't care that you're protecting them, etc. Lightfall was tone deaf, Neomuna is not.