Why this worry is reasonable
The concern
The objection, stated properly
A child is stuck — on a maths problem, on a paragraph that will not start, on a question about why the moon changes shape. That stuck feeling used to last a while. Now it lasts about four seconds, because there is a box on the screen that will answer. The answer arrives, it is good, and everybody moves on.
What makes this a real objection rather than a grumble is that effort is not a side effect of learning. It is closer to the mechanism. Working at something, getting it wrong, holding a half-formed idea in your head long enough to test it — that is the part that does the building. A tool that removes the effort is not obviously separable from a tool that removes the learning, and you do not have to dislike technology to notice that.
The worry also has a long and serious history. Writing was going to weaken memory. Printing was going to make people shallow. Calculators were going to end arithmetic, and search engines were going to end knowing things. That history usually gets deployed to close the argument, and it should not be. People worrying before and being wrong about the details is not evidence that they are wrong now — each of those tools did change what people were good at, and those changes were real. The honest position is that the question is open, not that precedent has already settled it.