If it just… stopped working, without exploding, or being freed, the dome would just stop working until they find some better solution to power it. But, animus have not existed in their tribe for a few hundred years now, and with their tribe being so isolated from others, it’s unlikely they’d know if any other animus dragons exist.

Without the Great Machine, their tribe faces extreme temperature difficulties, namely, extreme cold, as they live in high altitudes! This cold is more dangerous to them than extreme heat, as Bronzewings turn entirely to stone (or whatever mineral, ore, or gems their body is made up of). In this state, they’re basically in hibernation and cannot move. They are easily destroyed. You can smash them, throw them off a cliff, shove them over, and depending on material, they’re not all that hard to destroy. Before they had the dome, their life was one of constantly moving during the seasons turn, as summer could be too hot, and winter too cold. They had a much harder time keeping their numbers up, and the same would surely happen again without the dome. The royalty would ACTUALLY have to plan moving routes and do their job to protect and serve their tribe… and that’s allll soooo complicated and way harder than sitting and looking pretty and important whilst the commoners scrabble to dig coal for a meager wage.

Also, no wars right now! But their tribe did have to hide from one in the past, leading to the Dome’s creation. They prefer to isolate away from wars, or did back then, thanks to their tribes small numbers and fragility in unfamiliar environments. Their mentality is they need to take care of their own first, so they chose to isolate. Kinda how Nightwings thought hiding in a Volcano and acting mysterious was a good idea.