Have you read "Bowling Alone" by Robert Putnam? It's a tad outdated, but describing the same trends of growing loneliness and isolation. And sure enough, the author concluded that television was a factor (though not the primary factor.)

The book makes its case through data. Lots of clear charts and a great appendix at the end. The author spends a lot of time discussing his methodology and potential problems with it.

I tend to be skeptical, like you are, of "sky is falling" research coming from academia. Especially when the conclusion is that TV is bad for us (Sounds like my nagging parents trying to get me to play in the back yard!). But after reading this book, I'm stumped. I can't say the author is cherry picking the data. Surely there are limitations to the research, and the book is upfront about them. No, there is definitely something going on. The research makes that clear. And electronic media is likely a part of the explanation.

Really simple things like counting how many people folks talk to in a 30 day period can illustrate the bigger point. It’s a real problem.