There is a difference between being friendly and being friends.
A friend can be someone you have not spoken to in decades but they will help you in a time of need and pick up with you as if it was yesterday.
In a workplace you may adore your colleagues and spend more than forty hours a week in their company but are you being friendly or are you friends? There is a difference. It is not often that a workplace friendship arrangement becomes a true friendship.
In previous times people were not hypermobile. People did not travel on vast commutes just for a highly specialised job. They could get work on their side of town. They could also sell up and move that bit easier for that job out of town.
In a workplace you are not going to become best of friends with someone who lives a 3-4 hour journey away from you as you know from the off that it is a long distance relationship. The drink after work will be as far as it goes.
Of course there will be exceptions.
I am not sure that the older generation have that many close friends anyway, plus there was the stay at home mum phenomenon back then and whilst 'daddy went to work' the true friendships were made by the kids, bringing their respective parents together. Kids don't get chopped and changed like how jobs do so there is more scope for friendships being made through them.