Why was the early progress of science so slow? For the most part, knowledge is very hardly won, of course; but institutional and societal impediments are also relevant. Until well into the nineteenth century the Church was attracting and sequestering some of the ablest intellects, perhaps most of them. Science was too risky, and offered too few stable positions, and those that it could provide were supported only at low salaries.
It is possible to infer, therefore, that the progress of scientific knowledge was driven by those who could either afford to take the risk, because of private means, or those unable to prosper in the prevailing order, which was predominantly a status arrangement, for whom the inferior avenues offered by science and by engineering were the best available. These were not just second tier intellects, though one suspects that this was often the case, but also the socially maladroit who are frequently excluded in any status system.
As we all know, the last century changed all that, and growth in the available data and propositions to describe that data, grew at we now think of as the usual exponential rate.
Recently, things don't seem to be quite as rapid. Why is that? For the most part, knowledge is very hardly won, of course; but...