A common reaction to first encountering scientific insights such as evolution by natural selection is: "How obvious, why didn't I think of that?" A second characteristic of such ideas is that, thanks to their seemingly-obvious nature
, they are usually much anticipated before being definitively defined. Finally--and perhaps explaining why despite appearing to be self-evident they nevertheless take real effort to establish as accepted truths--the idea in question is usually highly controversial.
An insight you could add to the list is hyper-mentalism. This grew out of the realization that autism features symptomatic "mind-blindness:" in other words, major deficits in our species' normal ability to understand other people's behaviour in mental terms such as intention, emotion, belief, etc. As such, mentalism can be broken down into its components, one of which is gaze-monitoring. Where people are looking and how they are looking can tell you a lot about what is going on in their minds, but autistics are symptomatically deficient here: they tend to ignore gaze and to be insensitive to its significance. This is why you could call it an instance of hypo-mentalism: too little mental inference. But paranoid psychotics often go to the opposite extreme of being so pathologically sensitive to gaze that they imagine they are being watched or spied on: an instance of what you could call hyper-mentalism.
Autistics tend not to be good at participating in groups, which demands understanding of shared attention, but paranoiacs exaggerate sensitivity to groups and shared attention into delusions of conspiracies. Other people's intentions towards you can be good or bad, and autistics are symptomatically poor at appreciating either. But paranoid psychotics pathologically over-interpret good intentions into erotomania (the belief that others are in love with you) or bad intentions into delusions of persecution (often noxiously allied with delusions of conspiracies). Whereas autistics are characteristically deficient in a sense of self and often have impoverished self-awareness, psychotics can inflate their sense of self into rampant megalomania fed by delusions of grandeur. Where autistics tend to be literal and candid thanks to their mentalistic limitations, psychotics' hyper-mentalism facilitates bizarre self-deception and elaborate, self-sustaining delusions. Whereas autism can be diagnosed in infancy, thanks to its hypo-mentalism, psychotics have to acquire normal mentalism before it can hyper-trophy and be diagnosed as a pathology in adulthood. And so the list goes on...
Once you see this pattern it seems self-evident, and a number of others have groped towards the concept of hyper-mentalism with terms like "hyper-theory of mind," "hyper-reflexivity," etc. But to fully develop insights like this, you need something extra. Darwin provided the extra natural selection needed by being the pre-eminent naturalist of his day, and today genetics provides the ultimate scientific foundation for natural selection. The same may be true of hyper-mentalism thanks to the fact that the remarkable antithesis between autistic and psychotic symptoms can also be founded in genetics and cell chemistry, and shown to reflect fundamental symmetries in gene expression, cell-surface receptors, brain physiology, cortical connectivity, and so on. In short, autism and psychosis can be shown to be opposites in many important and fundamental respects, but the key concepts where psychology is concerned are hypo- and hyper-mentalism.
However, there is a crucial difference. Hypo-mentalism—mentalistic deficit—is widely accepted as a key insight in autism research, even if it is often described in other terms. But hyper-mentalism is different, and again like natural selection seems set to encounter bitter resistance and to attract vituperative criticism. Furthermore, the reason why may not be so different. An unavoidable inference is that, if psychotics hyper-mentalize, then so do seemingly normal people. So-called magical ideation is a key component of psychotic hyper-mentalism, and measures of it correlate with incidence of psychosis years later. But magical thinking is canonized in society as common superstition, sanctified as established religion--and nowadays increasingly secularized as media manias, ethnic mythology, and political paranoia. The result is that, just as Darwin found, a seemingly obvious and much anticipated idea can become highly controversial when fully spelt out and rigorously elaborated. Nevertheless, as the history of Darwinism has also shown, this is the only way that science progresses, and so why-didn't-I-think-of-that insights eventually become self-evident truths, however much antagonism they may at first arouse.