Care to explain how you think that is by design? I think it's more a side effect of trying to measure everything or design a system that is easy to measure.
When a culture/society becomes intensely class-stratified and divides into an aristocratic (British posh) and serf (British prole) structure, this kind of educational system (one tier for the aristocrats, another for the serfs) is very likely to arise. It may not be 'by design' as much as something that develops over time and becomes an unconscious social norm.
The driving force behind this is that the well-paid jobs requiring certain skills like facility with maths, excellent reading and writing and verbal communication (presentation) skills, etc. end up being reserved for members of the aristocratic class and are obtained more by social connections than by some open competitive process. These include professions like lawyers, corporate managers, etc.
Hence, the educational programs for the serfs are cut down to the bone (as the serfs are not going to need those skills in their jobs as assembly line workers, miners, agricultural field hands, janitors, etc.). This of course helps perpetuate the class division in such stratified societies. Incidentally, encouraging contempt for education and skill development in the serf class is part of this whole problem. "What, do you think you're smarter than everyone else?" etc. Kids getting bullied for getting straight A's etc.
There has always been a strange borderland between these two zones, however, where the technologically adept can arise and prosper. Michael Faraday is perhaps the best example of a member of the serf class who broke the pattern.
The notion of a conspiratorial cabal of aristocrats plotting together to sabotage working class education in the name of preserving their exclusive privileges makes for good cinematic content, but I'd guess simple indifference and the desire to pay less taxes is more of the issue.
I think it's disastrous to the long-term success of any nation, however. If America continues to slide towards such a system, it will fall behind China in technological development. Britain seems to have suffered from this issue: even though Britain was an early leader in computer technology (Turing, Colossus, etc.) they never had a Silicon Valley moment.
> The notion of a conspiratorial cabal of aristocrats plotting together to sabotage working class education in the name of preserving their exclusive privileges makes for good cinematic content
The "Progressive" model of education was very consciously planned with the intention of keeping the riffraff down, and far away from "elite" studies. It's "Progressive" in the early 20th c. sense of that word.
Of course one can also err in a different direction, devaluing practical education altogether and leading to "overproduction" of aspiring elites that are wholly parasitical on their surrounding society. And the two problems can even coexist, as seen in the US today! Extreme credentialism at the highest end (due to elite overproduction) coexists with the most dismal failure to achieve even basic educational outcomes for the bulk of the population.
