It could very much be that kids that grew on TV have some other thought patterns that caused the reality we live in today. It's extremely confounded on so many things. We cant really know for sure anything about it.
The fact that some knowledge and intelligence is not accessible to science (today) doesn't mean it doesn't exist. Just that we don't have the tools to study it, yet.
I doubt it. We reward some behaviors differently in 2020 vs 1980, and have different inputs from an information perspective. But people are wired the same way. The "racist uncle" stereotype of 2020 was "Archie Bunker" in 1980.
And no, high iq is not particularly useful in other areas, not when I don't have the ability to work hard on anything except what I'm actually interested in. So formal education was painful.
I don't put much stock in intelligence assessments. There's no real standards around the exams. My school placed you in cohorts based on IQ, and it was pretty obvious that the scoring system was measuring something other than your innate ability. My dad worked in civil service for many years, where promotions and appointments are governed by exams that were a combination of grammar tests and proxies for IQ exams. I didn't see any evidence that those assessments did anything other than reducing patronage and making it harder for non-native speakers to move up the ladder.