It would be nice if we could just memorize and recall anything with little effort, but alas, no. The brain is naturally going to gravitate to the most efficient (for itself) solution. The brain's job is twofold: to store information as memories and process it/try to optimize that as well as it can. The thing is, once we know where to find information, we know not to rely on our imperfect memory and just learn the location of that info.
If you had a source of information (say a train timetable) and you knew that you would have access to that timetable via your smartphone at any time, you are going to spend little if any effort on memorizing that timetable (assuming you needed to know more than just 1-2 arrival times). What you will memorize extremely well though, is that reference - the address of the timetable on the internet or the location of the file on your phone.
I really really want to find the study, but I can't at the moment; anyway, it's a fairly logical conclusion. Give two groups a bunch of information they need to regurgitate on an exam. Tell the control group that they will not have access to the information after the time is up, and then store it in a file cabinet. Tell the test group that they will have access to the information (provided they can remember where the information was stored). The control group obviously can give much more information by memory, but they couldn't tell you which drawer of the cabinet it was in. The test group doesn't remember a whole lot, but remembers exactly which drawer and what the folder looked like that the information was stored in. And then the test group obviously does much better on the actual exam at the end; they have all the info.
There is no reason genetically to suggest that we are getting "dumber" in any way. We are the same species we have been for thousands of years. Our information structure is changing rapidly however, and it is interesting to see how we are adapting to it.
Your point was that these kids are all going to be led away from whatever they find on Google. But, as someone else pointed out, that's way more information (more viewpoints, etc) than was available to previous generations.