Part of the endgame for a modpack like this isn't just the machines in your base or spiffy armor. For some people it's building that oasis in the ruins of an old city. Some of the stuff i saw on other servers were modeled after fortresses, or glass domed enclaves. Others were madmax style rambling structures with bridges connecting various levels of buildings and zombies roaming below.
'Endgame' is an odd term for minecraft. It can mean "i've done all the quests, like in Agrarian Skies, or killing the enderdragon, or just "built the best item i can get, bored, moving on". Oddly enough, the longest running servers seem to be vanilla. Something about having a progression in modded MC means people think they have to leave when done and start over. But servers with a good community can beat that. To build community people need to stick around. That's the bad side of raiding. One guy has a great time destroying stuff someone took weeks to build. He had fun. Builder leaves. If it's just PVP in the ruins, not so bad. You might lose some stuff, no big deal. You still have your machines, town, crops, progress. It takes a lot longer to build than to destroy. So it a lot easier to get people who raid to stay around than the people that built.