When the Purge was first being discussed (prior to any release of details or in-game footage), I had envisioned an event designed to wipe ALL player bases. In other words, it wasn’t expected for players to survive the event. Whether that was an environmental disaster (like a Pyroclastic cloud from the volcano going off with massive poisonous ash clouds and lava flows, a meteor storm of starmetal impacts [doing damage to exposed bases], Avatar sweeping-attacks, or massive swarms of NPCs [like an army, not a couple of guys with a stone spear between them], a gale-force sandstorm that could rip flesh from one’s bones lasting for days, or whatever). And only the highest level characters with extreme bases would have even the slightest chance of surviving intact (or mostly intact). And this would happen, perhaps, on a monthly basis. Thus, no one could really get “settled” because of how dangerous the land was. There would be this constant ‘re-building’ with each “season”. It could even encourage players to work together to be able to survive the next massive Purge coming up (and sheltering low level characters).
And then, the Purge came out and it was this small band of NPCs attacking a base in a few waves for a short time. 
So I think the game could be challenging for high level PvE game play if they crank up the Purges to something ‘server-wide’ rather than player specific. But not in its current state.
In my opinion, the game sorely needs to focus on re-playability. And I agree, not “dailies”. But world events. And there are good mechanics already in place, that with some expansion, could be tweaked to accomplish this. But first, the AI/Thalls/Siege mechanics need fixing (which is being worked on right now). But the Purges could be so much more than what it is right now. And made into a real, survival PvE experience.
Put simply, the PvE world of Conan Exiles should feel dangerous. The environment itself should be dangerous enough to low level players, that meeting another player should bring a feeling of relief (someone to help keep you alive and cooperate for each other’s mutual good) rather than a competitor fighting over the scraps the world has to offer. And similarly, resources should be more difficult to come by – exiles are showing up in a region already “ruled” by factions of people who have been there for a while. Players should ‘want’ to work together for their mutual survival (such as pooling what little they can find in order to create more advanced equipment – more advanced than stone tools and basic tents). High level characters should be concerned by triggering factions (such as politics and even ‘war’), base management, and unique, world encounters and events. The world should feel dangerous to both low and high level characters, but for different reasons.
Side Note: I would also recommend resources be set to “expire” and randomly show up in different locations periodically. This would help encourage players to ‘not’ camp specific nodes and get them to actually venture outside their walls to look for new resources. Camping a spot only makes economic sense if the resource never dries up.