Descartes Shaman seems like a gratuitous philosophical name drop, until you realize that the philosopher Descartes is the creator of the idea that a person can to only truly know their own mind, which is the origin of Solipsism. The series' setting, however, provides a way to get around the trappings of Solipsist thought: GN Particles and quantum brainwaves, which allow people to connect their minds and experience another view point, confirming the existence of minds outside one's own.
The movie within a movie adaptation that dramatizes the work of Celestial Being is also an example when you think about it. In this dramatization, Alejandro Corner is made the main villain and the leader of the A-Laws, even though he was killed at the end of the first season, before the A-Laws even existed. This might make no sense except when you realize that making any reference in the movie to Innovator or the Innovades (the actual villains), would lead to a public backlash against the Innovades, which would cause problems since the ESF is making use of the re-purposed ones (although their existence may be secret anyway). It would also probably lead to a backlash against the emerging Innovator population since people would probably have a hard time discerning between Innovator (the organization) and Innovators (the stage of human development). Alejandro then makes the perfect fall guy for the evils committed by the A-Laws.
At first glance, the film appears to forget or ignore the very real possibility that the increase in the numbers of Innovators and public knowledge of Innovades would likely lead to a world-shattering conflict, similar to the one between Coordinators and Naturals in Gundam SEED. However, it makes sense in the 00 universe, where there would be the very real fear that any sort of large-scale conflict would cause Celestial Being to begin their armed interventions again. Considering the sheer amount of damage the 4th Generation Gundams are capable of inflicting (compared to what the units in seasons 1 and 2 could do, which was already quite large as is), that we're shown, it's probably in everyone's best interest not to incite anything.
It is also not completely forgotten, being brought up near the beginning when the ELS start targeting the burgeoning Innovators.
It's also explained at the start that after the crimes of the A-LAWS became public, it caused a huge backlash against military buildup in global scale, making everybody equally afraid of the possibility of war. This probably played a large part in avoiding large scale conflict, and the ELS ended up unifying mankind even further.
One of the side-stories makes reference to an anti-Innovator and anti-ELS war that happens sometime after the movie. Celestial Being ends up intervening in that too, as in one such altercation during the war, an earth-operation variant of the Raphael Gundam, Dominions, showed up and proceeded to vaporize one of the sides (The Old Human faction) by itself, from hundreds of miles away. It's very likely this conflict did not last very long.
Fridge Horror on that: Whatever happened to Sumeragi, Lockon II/Lyle, Allelujah/Hallelujah, Soma/Marie, the Vashtis, Lasse, Feldt, Kati, Patrick, et al., after 50 years? Simple, they could have died in that conflict.
One thing that I noticed where that the ELS are clearly shown to have regenerative abilities yet when Setsuna blew up ELS-Not-Ribbons it crumbled. Then it hit me that in order to function, the ELS need a certain amount of mass and if the mass falls below a certain threshold in a single ELS, then it is unable to maintain integrity and effectively die.