I guess 2 years is as much as you can expect a line like this to get. There have been quite a few of these relatively short-lived action/adventure themes like this, like Exo Force, Aquaraiders, Alpha Team, or Agents. I guess you could see Atlantis as a follow-up to this kind of theme. Hmm, isn't there a pattern in recent action themes?
2008: Third and last year of Exo Force, first year of Agents.
2009: Second and last year of Agents, first year of Power Miners.
2010: Second and last year of Power Miners, first year of Atlantis.