I would further theorize that Betterman takes place either during the events of The Battle of Jupiter from the GaoGaiGar TV series, or during the events of GaoGaiGar FINAL. since that would mean that most of the heroic people would be far from Earth at the time, allowing Algernon to capitalise on the fearful masses.
Going by the Project Z trailer, what was left of Akumasu and 3G (after the aftermath of Betterman's and GGG FINAL's respective bleak endings.) would need each other to survive, thus facilitating the mixture of Kakuseijin and Mechanoid tech to create GaiGo and GaoGaiGo, and for Mamoru and Kaido to arise as the world's new heroes, even if they are still just children. (Later changed to young adults in the novel series.)
To that end, Betterman shares some startling similarities in his duties and goals to Counter Guardians, but cannot be a counter guardian himself, as he still possesses his own will. Perhaps, then, he is not subservient to Alaya, the consciousness of humanity, but to Gaia, the consciousness of the planet...?
- Given Gaia's hostility towards humanity, the Algernon phenomena seems like a more likely choice, preventive measures towards human beings from causing destruction of the world via Cancer.
- Also, must the Sakura always suffer?