It's not dead until there is actually no players on the servers. Bo1 runs bad for some players. Especially for low end pc gamers. Since Treyarch did a bad job porting Bo1 to PC. A lot of the player base for plutonium don't have a mid end pc or high end. Which is the main reason for Bo1 not being as active where WaW,Bo2,MW3 were all optimized for PC.
Use this tool to see the player count and mostly on the weekend is the most active for Bo1
https://list.plutools.pw/t5mp
https://list.plutools.pw/t5sp