Each faction begins with specific factions being their primary enemies. Factions set up forward camps when their primary enemy has been defeated/destroyed.

For Lothlorien and Imladris, they will set up their forward bases if Dol Goldur and Moria are defeated.The Southern Evil factions will set up forward bases if Gondor is defeated. The intent isn't to make them stronger, it's to give them a reasonably close target to new enemies and a safe haven to replenish/resupply.

The updated forward bases extend range of campaigns, patrols, and caravans. If these didn't spawn, the factions wouldn't be able to move on to new enemies once their primary enemies are defeated - Elves would never target Southern settlements for sieges and each faction would be locked to their initial starting area.

This would seem to imply that if you are able to destroy the forward base for Imladris (Rivendell), they would stop targeting campaigns in that area.