I would say it's a golden age for TV series. I am not sure that exactly means it is a golden age for television as a whole considering the golden age of TV News, depending on what metric you use, is probably not now. Same for the golden age of talk / variety / comedy shows.
EDIT: I should add that when we think top quality recent TV serie, we often think about a single long story split in episodes and not shot exclusively in studios (by opposition to soaps). There are certainly things like that that predates The Sopranos. Wiseguy comes to mind.