Third places have been in catastrophic decline for decades. The book Bowling Alone: The Collapse and Revival of American Community came out in 2000, talking about the collapse of community activities and third places (and that book was, in turn, based on a 1995 essay written by the author).
Discussion of the collapse of third places goes back even further than that, though, the seminal work on the topic, Ray Oldenburg's The Great Good Place was published in 1989.
One of the reasons the show Cheers was so profoundly popular in the 1980s was because generations of Americans were mourning, whether they realized it or not, both the death of (and the crass capitalization of) the third place. Cheers functioned as a pseudo-third-place that millions of people sat down to watch every night to feel like they were going to the third places that were fading from the American experience.
A lot of people don't think about it, but part of the death of the third place is the crass capitalization mentioned above. How many places can the average American go anymore without the expectation that they spend their money and get out?
Sure, many current and historic third places have an element of capitalism (after all, the public house might be a public house, but somebody needs to pay the land taxes and restock the kegs). But modern bars and restaurants fail to fulfill the function of a pub and most would prefer you consume and leave to free up space for another person to consume and leave. The concept of the location functioning as a "public house" for the community is completely erased.