What changed then was stranger danger. With schemes such as 'Neighbourhood Watch' (in the UK) people saw strangers as potential threats, just there wanting to break in, steal the VHS player and sell it for heroin. Strangers were not welcomed as visitors, that was not the default.
Much else happened then to destroy community and make it so everyone was out for themselves. In the UK we also had the privatisation of social housing and the privatisation of public transport. The car became king and the poor could end up being those terrifying homeless types that nobody likes to see but take for granted nowadays.
In generations before Thatcher/Reagan there was TV and that apparently destroyed community. True we might not have been going down to the church hall to have a dance or to play board games, however, at least with TV families watched programmes together in the front room. Plus with only a few channels you could talk about TV with people in ways you can't today. There was still a national conversation, even if it was about what David Attenborough had brought to the small screen the night before.
Community is the enemy of consumerism, if people are sat in a public space enjoying company then they are not in their cars going to shops and buying commodity entertainment. But consumerism has kind of died too, people do not shop like they used to as any mall can testify to.
Despite everything that is wrong people are innately wanting to have friends and be part of a community. This will never go away, even if those needs are currently met by proxies in social media and opioids. Although Thatcher grade leaders may want everyone divided and living in an atomised society, human nature will win in the end. Long live the revolution.