Maybe we are adapting to skimming, filtering, and jumping from source to source of information.
Given that this is the way the (modern?) real world works, I don't see it as a problem.
The only drawback is the sentimental loss of no longer being able to sit down and be completely focused on a single thing for any length of time. Whilst this may be a shame, the fact is that such an activity these days is purely recreational and probably impractical for most people anyway. Time has moved on and so should we.
Amassing more data from diverse sources is in no way superior to gaining deep insight/understanding by focusing on, and thinking through a particular topic. Have you ever had an argument over the internet with someone who doesn't even understand the fundamentals of what he's arguing about, whose response is to blindly regurgitate what others have correctly or wrongly posted elsewhere, whose stock reply is "But this website says..."? That is a product of this skimming culture.
When you skim sources, do you remember the details of what you read a day later, a week later? I know I don't, and I'll wager many others don't either hence the popularity of keeping bookmarks, saving files, apps like Pocket etc.
If we don't even remember the details, how can we ever formulate anything beyond a superficial understanding of what we skimmed? It's a safe bet that Newton would not have been able to write the Mathematica Principia if he skimmed mathematics texts. I'm certain you would not like it if your doctor skimmed his medical texts in med school. I don't think you will be happy if your lawyer skimmed through law journals while preparing for your case.
Skimming has its uses, but loss of focus is not the 'sentimental loss' you claim it to be. There will be times when you want yourself, and the people you deal with, to be focused like a laser.