It kind of always circled back so they left after couple of times. But I'm sure it depends on the group. If the group serves some purpose (like organizing some meetups) people definitely stay for longer. If it's for talking shit I don't think it works well. Same like social media.
More ephemeral, voluptuous and hydrogenous!
I had couple of fairly diverse group chats and the more sensitive people left real quick. In my experience you can discuss politics or economy among friends with different views but when you touch social issues it gets toxic real fast. Pretty much like on social networks.
From what I see California doesn't have any nuclear weapons on it's territory so I'm not sure if they would be able to resists any attempts of federalization. I don't mean they will get nuked but army will be send in response to any attempt of secession and state army will have no chance against US army. Having nukes could protected them but they don't have any.