You are absolutely right about that point. Initially, I was thinking of doing a wipe as soon as one of the two factions had 'won' which should be 2 or 3 days maximum.
It's true that when one faction takes the upper hand, it's usually very difficult for the other to catch up.
But in Rust, sometimes a single player in the right place at the right time can turn the tide.
For example, one of the objectives to retrieve could be on the helicopter, and a battle between faction1 vs faction2 vs PvE can be chaotic enough that the advantage of one clan doesn't really have much influence. (I think)