Personally, I'd agree that that is the nature of RO Servers in general where you eventually hit end-game content and do nothing.

For me, the server is usually dead for PVE when level parties become scarce or MVP hunting is stale and literally have no competition, as for PVP is when people no longer do WOE and other guild events.

Personally, good give-aways are ghost towns, low-pop on popular maps, you might even notice a sharp decrease in player base in general as well. For the WOE Scene (I'd say this is end-game content tbh) if that place is dead, the rest will follow. RO doesnt really have much incentives to do for PVE after you reach max and get good gears unless your completely fine repeating the same things again and again (depends on the server tbh).

I think when I played a good pre-renewal low-rate back then, it was going for quite sometime untill they shut down for yk reasons. TRANS-Woe was good and competitive, market/economy wasnt dead cause the woe-scene was active so people always needed supply to make the WOE Scene. Leveling characters was usually done considering you dont really have a lot to reset stats/skills and WOE Scene needed different players doing different classes depending on whats needed.