> There are studies about declining IQ in the last decades. Probably mobile phones and social media are to blame.

It is much more nuanced than that.

The long-term rise (Flynn Effect) of IQs in the 20th century is widely believed to be driven by environmental factors more than genetics.

Plateau / decline is context-dependent: The reversal or slowdown isn’t universal, like you suggest. It seems more pronounced in certain countries or cohorts.

Cognitive abilities are diversifying: As people specialize more (education, careers, lifestyles), the structure of intelligence (how different cognitive skills relate) might be changing.