I saw similar cycles of activity when I hosted a minecraft server. Player towns would build up, grow stagnant, and become ghost towns in 2-4 month cycles. Often a new game would come out and player count would dip. Old players would achieve their goals and then find they have nothing new to strive for.
Every 10-12 months, we would wipe the server and everyone would start fresh. The reaction was predictable- many players would be upset or sad to lose all of their hard work. Some would vow to never come back- some actually left, but most returned. But the real benefit (besides re-seeding resources back into the map, MC has no built in regen after all) was the spike in player activities and interaction. Players built cities again, traded for resources they did not have, and pursued new goals.
Boundless is designed to be persistent, and server wipes would be catastrophic toward that design philosophy. But it would hugely benefit the game and community to have some way to experience that fresh wipe rush of activities that minecraft servers get after a wipe. I’ll shamelessly plug my existing suggestion for seasonal content here… Seasonal Planets