Material conditions certainly affect this too.

For example, if you're younger, it's a lot harder to throw a dinner party in your tiny overpriced apartment than it might have been for a previous generation of people who already owned homes in their twenties.

It is also harder to throw a party when both partners in a relationship need to work full time to make ends meet.

It is also harder to throw parties when invitees also are overworked and tired and are habituated to netflix, rather than going out.

If you live in a city, going to a public space is inevitably easier. If you live in a suburb, staying home is inevitably easier.

It's much more plausible to me that these trends are due to underlying material conditions more than they are to some fundamental change in the social attitudes of people (though obviously both can play a role).