The entire network can be down. Its just harder as there is some built in redundancy. I’m sure reddit also has built in redundancy.
When my local instance is down, I use my alternate. Its much worse as its not as curated. Sure, there are apps to help sync them now but my instance is now reliable enough that inhavmt bothered.
I think it’s important to be realistic in the capabilities of Lemmy in looking at competing services.