Assuming the forums also go completely down and the discord becomes inactive, then idfk.
What other forum based games even are there? Dwarf fortress is the only one i could think of.
Im sure some people would move to yomi hustle or something but personally id probably just stop interacting with the community other than a few people :L
But yeah tb dying would suck, dont think there would really be a long term replacement for toribash, atleast for me