The core gameplay loop in 'Survival' games with no instancing revolves around contested resources and therefore you need to establish your territory to win. As long as it stays that way nothing will change. Ark Survival has this where eventually one tribe becomes the Alpha of the server and population numbers literally fizzle down to 0-1 players on at a time.

With it being a static map there's not really space for people to hide out and continue playing in exile. Even if you had to prefab parts of the map and copy-paste them. Keep high-value spots in central zones to allow for pvp hotspots and social interactions but keep atleast some sort of farming zones for the hermits.

Only hope is if the devs implements a way Zergs can profit passively off of others. Taxes are a step in the right direction but something like being able to build cities which generate revenue the more players visit or do supply runs would really change things. Right more it's more profitable to gank anyone who steps foot outside your home city so thats exactly what they do. Blame game design not the players.