Are they??? And yeah no gods.... Still archfeys, demons arch demons and plenty of god like beings that while not technically gods.... Effectively...are the same but without restrictions.
This isnt mankind vs gods. This are 8 people that, at their whim, decided the world would be better without gods.

And now.... They are at the whims of nature, of Kings and anyone in power. After the calamity the gods can't just intervene (they need to agree, or however the divine gate works).
Now what they achieved is... No miracles and everyone can suck it.
#CriticalRoleSpoilers

And now that two ruidusborn just took the gods away. The very religious orders of Exandria will try to kill ruidusborn and ruidians. A lot of people will die because there are no gods. You can reason with the gods, you saw them at their worst and they were reasonable. #CriticalRoleSpoilers

Can't they survive??? The civilization was pretty good up until now.

Hell people rely on gods to survive... They were not under an oppressive regime. They just didnt like that there was someone above them.