The solution at the time largely involved not letting groups unlikely to be educated… vote at all.
I’d definitely be interested in evidence that there are democracies with voters who are significantly better at understanding the function of their government, the breakdown of the budget, how basic functions of it work, et c, than in the US before, say, 1975.
I'm not totally sure whether you meant the 1975 point as a comparison of democracies today versus 1975 US, or democracies from 1975 compared to the US.
This is anecdotal since I don't have evidence handy, but I've been impressed with Swiss voters that I've met and they have all spoken highly of both their Democratic model and their voters. I don't know all the intricacies of it, but my understanding is that their system pushes any meaningful change to a vote. Its slower and requires more voter engagement, but at least from my experience that has succeeded in building a better informed public.
I’d definitely be interested in evidence that there are democracies with voters who are significantly better at understanding the function of their government, the breakdown of the budget, how basic functions of it work, et c, than in the US before, say, 1975.