I think about this question a lot myself! And I have come up with a few answers to why this might be possible:

1.People in general are more prone to selfishness and manipulative behavior compared to earlier, say the generation of our parents. It has become a common occurrence and we have become used to not expecting too much from everyone. This in turn narrows down our friend circle and hence the people we talk to a lot has reduced.
2.We have filled our lives with way too many activities and have less time to devote to have meaningful conversations. With social media and increased options for almost everything around us, we are always too occupied.
3.People by nature have become a little less tolerant towards diverse views and viewpoints and hence prefer to stick to their own beliefs and opinions- hence mingle with those who support these.
4.Technology! We used to meet up people and friends to discuss lives and things which matter- now it happens in 140 characters over digital media. What is left to talk when all of it is happening on Whatsapp?
In my close friend circle, we prefer to keep our phones stacked in the corner when we meet. To be really present and just converse :)