(CNN) Two major hits, "Game of Thrones" and "The Big Bang Theory," are signing off within days of each other. Whether those shared viewing experiences represent a celebration or a wake is once again the subject of debate in TV industry circles.

When it comes to bringing millions of people together, TV executives are fond of saying that the pipes still work. That's certainly been true during the build-up to the finales of "Thrones" -- which has broken records for the pay-TV network -- and the CBS comedy, which concluded its 12-year run Thursday with an estimated 18 million same-day viewers, per Nielsen data, a figure expected to grow to 25 million with delayed viewing.

HBO's mythical drama soared to an all-time high with its penultimate episode -- with 18.4 million viewers in the US -- and despite ample criticism and venting on Twitter , seems likely to eclipse that mark with Sunday's finale.

The lingering question is whether in an age of watch-it-your-way viewing these sorts of shows can be replicated, or whether each successive generation of "hits" will inevitably be narrower and more siloed off than the one that preceded it.

This discussion is hardly a new one. Each time a major hit goes off the air -- "The Cosby Show" in 1992, "Seinfeld" in 1998, "Friends" in 2004, "The Sopranos" in 2007 -- there seems to be a new round of speculation regarding whether TV has crossed a bridge into what amounts to a smaller, more dispersed world.

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