It may be that the last step from the triangular region of acceptability to a probability function s(x) was huge for many readers, who are – perhaps – not even familiar with the Gaussian distribution and its moment matrix, M.
The figure below shows a region of acceptability enclosed by two lines. s(x) = 1 between the lines and s(x) = 0 outside.
The red cluster consists of points determined by two independently Gaussian distributed parameters x1 and x2, with variance = 1 in both parameters.
After a sufficiently large number of generations with adaptation of M according to the theorem of GA, the increase in average information (entropy, disorder, diversity etcetera) may result in the green cluster. Actually, the mean fitness - i. e. the probability of becoming a parent to new individuals in the population - is the same for both red and green cluster (about 65%). The effect of this adaptation is not very salient in a 2-dimensional case, but in a high-dimensional case, the efficiency of the search process may be increased by many orders of magnitude.
A pop-scientific interpretation of an increased average information is that it gives more information in the art of survival not considered by "Fisher's fundamental theorem of natural selection", see special thread.
Thus, if the lines are pushed towards each other – for instance because of arms races between predator and prey – the adapted process is more able to get away from the dangerous point of intersection between the lines and extinction may hopefully be avoided.