The collapse of genius in Britain happened very quickly indeed, in a single generation: my generation, in fact - those born from 1945 onwards (but in England we don't use the phrase 'baby boomers').
How could this happen - I mean so abruptly?
Of course, there were still some elderly geniuses still around in 1990, and some are still alive - but the supply is cut-off.
There aren't any recognized, active, genuine geniuses in England today - whereas a century ago, and two centuries ago, they were thick on the ground.
Even though I believe that average intelligence has been declining very rapidly since the Industrial revolution (due to some mixture of accumulating genetic mutations in from very low child mortality, and a differential fertility pattern adverse to high intelligence - and more recently mass population movement) - even though I think it possible that average intelligence may actually have declined at something like 1 IQ point per decade...
Even despite all this; the abruptness of the collapse of genius was still too rapid to have a biological basis in terms of the actual production of potential geniuses.
So I assume that the problem was not actually in the production of genius people but in a collapse in the ability to recognize the products of genius - the failure to perceive and to use genuine breakthrough ideas and products - and that this was substantially due to very rapid social changes happening in England through the 1960s through 1980s.
What happened, I think, was that the production of geniuses declined rather gracefully, gradually, incrementally - but that it was that the ability to evaluate and recognize major work of genius that collapsed abruptly.
The idea is that creative genius - the ability to make breakthroughs - is extremely rare because it requires a combination of high intelligence and high 'Psychoticism' - which is a personality trait defined by Eysenck that include both high creativity plus a constellation of personality attributes most of which are helpful or necessary for a genius.
However, the role of the genius is essentially to produce products of genius which can be exploited - by society. Therefore, a society must have the ability to recognize and use the products of genius.
To recognize and exploit the products of genius - a new theory or equation, an invention, a technique - requires a much lower intelligence and creativity than first devising it - and there will be something like ten or even a hundred-fold more people in a society who can recognize, understand and exploit the products of genius than can make significant breakthroughs.
Yet, although genius exploiters are much commoner than geniuses, to recognize genius nonetheless requires some elements of genius - early users require substantial intellectual abilities and some elements of a creative and autonomous personality.
My idea here is that as the frequency of of production of geniuses declined throughout the period from about 1800, this was accompanied by a decline in the proportion of the population capable of recognizing, understanding and exploiting the products of genius - and during by the 1960s this pool of genius exploiters had reached a critically low proportion in most areas of national life - and during the 1960s into the years beyond, rapid social changes caused a sudden dilution of genius-product recognizers and genius-product users until by 1990 they were outnumbered, overpowered and ignored.
By 1990, the English had not only suffered a long term reduction in the proportion and number of creative geniuses, but English society had also become incapable even of recognizing genius; and unable to detect and use the products of genius.
There are numerous possible contributing reasons why English society and its institutions may have very rapidly become incapable of recognizing genius; all or several may be true, and I don't know which would be the most important.
These include the rapid expansion of higher education (universities and colleges), the collapse of 'meritocracy' (i.e. a system which allocated roles primarily on the basis of functional ability) the transition to a sexually-mixed co-educational workforce, the rise of 'affirmative action' in terms of a system of group preferences favouring those groups with the lowest frequency of occurrence of the attributes of genius, and of genius-recognizing capacities; a massive shift of national focus away from social functions and towards sex (i.e. the sexual revolution); the rise of the Mass Media and bureaucracy; and of course the collapse of Christianity as the dominant national religion - accompanied by the collapse of honesty, ethics and devotion to beauty.
By 1990 and since then, England had become a society where there are no acknowledged geniuses, and the relatively few people capable even of recognizing the products of genius are few, scattered and powerless - so social evaluations are dominated by fashion and expediency; and the primary societal ethic is of conscientious conformity to the oscillations of fashion and the winds of expediency.
There are, I think, still men of genius; and still a few people who recognize them and (more importantly) can recognize the potentially revolutionary breakthroughs which could (if adopted and exploited) transform societal function.
But there are not enough such people - so their effect is extremely diluted, and they are not in positions of influence, and they do not make any perceptible impact on the major social institutions of England today.
In sum, England gradually lost her innate ability to innovate from about 1800, and this was accompanied by losing the ability to recognize and exploit innovations - but this decline (being much common) lagged the decline of genius by a few generations.
But from the 1960, the proportion of people who had enough genius in them to be able to recognize and exploit innovations - and has the kind of independence of personality required to hold by their own unusual understanding - had also become critically low - and the social revolution from the mid 1960s triggered institutional changed which very suddenly and abruptly overwhelmed not only the geniuses but even the genius-detectors.
In England nowadays, the competence even merely to recognize work of genius has become rarer than the occurrence of actual creative genius used to be.