Yes, The Economist is difficult, but whether it is demanding will depend on what other prose you consume on a regular basis, and how much of it. I do not find it gratuitously abstruse in the way I do academic writingacademic writing, something Pinker and others have criticized, for example.
There are a variety of English readability formulae, variously flawed but widely used, among them the Flesch-Kincaid tests, the Coleman-Liau index, the Gunning Fog score, and the SMOG index. By and large, theyThey calculate a score based on the number of letters or syllables per word and the number of words of different difficulty levels per sentence, which is then indexed against an age or years of formal schooling a native would require to understand a passage of text written at that score. There are many free websites that will score a passage of text for you.
The Contently blog scored popular articles on various news websites using a mix of these scores, with over 12 years of formal education estimated as needed to understand the article from The Economist. By comparison, the article from the New Yorker scored about 11, the New York Times a bit under 9, and Cosmopolitan magazine a little over 6. While these results are not from a scientifically valid survey, scoring your example passage with the same metrics returns an average of 11.8, suggesting that it is at least more difficult than average.
Is it artificially complex? I doubt it. Consider satire newspaper The Onion's old point-counterpoint entitled "According To The Economist, NASA Is An Industrial Subsidy In Disguise vs. Oooh, Look At Me, I Read The Economist!" The counter-point position mocks an Economist reader he assumes wants to be seen as sophisticated or well-informed, not literary. The New Yorker or the London Review of Books might be presented for contrast.