So with the (upcoming) release of the new infested planet I think I should revamp my concept.
Prior to the Heart of Deimos announcement, the infested had a benign presence. Lurking but not harmful outside of the few quest or events like the plague star event or the certain Warframe quests like Once Awake or Patient Zero. Unless you were around in 2014 to play the series of events and operations that centered around the infested and gave them recent relevance and threat, including their evolution to infect non-organic life.
Below is a quick story/event outline if you do not already k