I'm afraid your knowledge is a bit out of date. Even Flynn has given talks about the "reverse Flynn effect" in the past three decades. IQ scores have been going down.

Recently: https://www.sciencedirect.com/science/article/pii/S016028962...

My suspicion on this is not the noise from the device, or even the devices themselves are the problem... It's that we sit on our ass all day watching/listening to them. Brain health is correlated to exercise and movement.