The Left has triumphed over recent decades by ratcheting incremental change in societal ideas - such that each new move can be seen as hardly-different from what already exists.
And 'public opinion' has been moved Leftward by truly massive, and now massively-policed, media saturation - and the use of exemplary punishments of public figures for real or imagined violations of the zero-tolerance policy concerning non-PC public (and private) discourse.
Yet the Left remains terrified by the insecurity of its achievement.
And they are correct to be terrified - because while it has taken decades to build up, the situation is held in place only by truly gargantuan efforts in propaganda from a mass media of astonishing size (backed up by equally vast bureaucracies of the state).
This is constantly pressed-upon by underlying human nature - which, the heavier it is pressed down and the tighter it is squeezed, the more extreme would be the behaviour if ever it 'got free'.
(This would not be a pretty sight, and its increasing horribleness leads to increasing efforts to make it not happen, and an increasing worseness when it does happen - in the usual fashion of these things. In fact, it is happening already, as people perceive for themselves - but is simply being disguised or excluded from public discourse.)
Indeed, it is probable that the situation cannot be held stable - but that the Leftist revolution must keep moving - keep inverting and destroying one after another of the bases of traditional society.
The basic modern situation, then, is Leftism versus human nature. In the old days, the Left denied human nature and regarded people as a blank slate to be written on: they still say this but don't believe it, because the need for propaganda and coercion continually increases, it doesn't 'wither away'.
The conflict between Leftism and human nature is particularly bitter and intractable because Leftism is intrinsically atheist and therefore can see nothing other than 'this world'.
(By contrast, the Christian conflict with human nature - which is itself a much more partial thing than Leftism v HN, and fully expected and indeed the very reason why Christianity is needed - is resolved, but after this life, one way or another.)
There is a solution for Leftism - a way it can win the conflict with human nature: and that is to change human nature.
(This was foreseen by CS Lewis in That Hideous Strength and The Abolition of Man.)
In a sense, the power and pervasiveness of the mass media is already a major step in this direction, since it is a qualitatively new situation - but clearly it is not enough.
As the limitations of propaganda become apparent, we can foresee the dawning realisation that humans will need to be changed permanently, by technological means presumably, in order that they conform to the world view of Leftism.
Of course changing human nature would not really solve the problem, as Lewis made clear.
But the the problem itself is the consequence of an incoherent - indeed demonic - ideology that nonetheless survives and thrives.
And from within this demonic perspective, changing human nature appears to be the obvious solution, merely doing fully, more efficiently and permanently what is currently done partially and at the cost of vast effort and with clumsy coercion.
The project to change human nature fits in with both the imperative of sustaining the 'progress' of the Leftist revolution and the self-interest of Leftist leaders in eliminating opposition once and for all - so it will very probably be attempted.
(Unless things collapse before that point.)