I understand (I think), what you are saying. But I'd also argue that, back in the day, Byte & similar magazines were targeted at a fairly small subset of the population.

Today, I think equivalent magazines are Make, Adafruit's blog, internet & all the resources available online. So, I think such magazines / content still exist & they still have an audience (if not a larger audience, thanks to MOOCs & Arduino / Pi, etc.)

If you are making an argument that, in general, most magazines today publish trash, and somehow, the magazines published in the past were more content rich.. I'd challenge that with two points:

a) Content heavy magazines / websites still exist --> Economist, Ars Technica, etc. They have a strong audience.

b) The pool of people reading has gotten larger; and more magazines are catering to a more diverse population, some of which, as you imply, are drivel.

But to say that such content is no longer published, or is accessible, I would think, is incorrect. I'd argue such content is much easier to access today than ever before.