People want community. They want a connection to real human beings, for conversation, for help, for information, for all the reasons that we as a species are basically pack animals.
Most of the commentary here is going to be United States of America-centric, because that is the frame of reference of the author. You don't have to go back very far in our history of our country to see a time when "community" was a much more common experience for the average American. There are many reasons why this is less so, or at least "feels" less so than in the past. A few of these:
The migration of many people into larger cities, away from smaller towns and rural communities
The rise of technology and the many ways that it allows us to connect with people while also making it very easily to isolate ourselves
The perceived (I say "perceived" here because in general the data doesn't hold up this assumption) that it is risky or even dangerous to connect with "strangers", even if they are our neighbors.
The current economic climate in America, which has encouraged people to continue to strive for material wealth at the expense of their time and their ability to dedicate resources to their community.
It's the last one that this author sees as the primary issue facing us today - people are tired. They are over-worked, under-paid and in general don't have the energy to think about much past what they perceive as their basic necessities, much less to think about what their community might need.
Many (or perhaps most) people want to be part of a community, but few tend to want to run it. Leadership positions are challenging; you are putting yourself out there for critique in every decision you make, big or small. This is the common refrain I see across community groups on sites like Facebook, Nextdoor or even reddit - people ask in a hundred different ways about how to be "a part of a community" but rarely do you see someone voluteering to create one or take a leadership position in an existing one.
And volunteering is the key aspect here - our time is valuable, and investing in a community costs us time above all else. There are also other ways community leadership costs us, but time is the most valuable. However, the rewards received almost always outweigh the investment.
Throughout most of humanity's history the principal thing that brings people together is food. It's not only a basic need, but the act of "breaking bread" with someone fulfills a need in us that goes back hundreds of thousands of years.
The reason we call this "Driveway Dogs" is literal: the idea is to bring your grill out onto your driveway, provide a few chairs and maybe a table or two, and cook hot dogs for people. The Driveway part is important for a simple reason: it's a low barrier to entry.
If you've ever been invited into someone's home, you know that there are countless social queues and expectations that go along with that invitation. Does this house take their shoes off at the door? Where do I put my coat? How many restrooms do they have? Do they have any pets? Do I need to complement that horrible carpet they put in the living room? And most importantly: how do I politely leave when I don't want to be there anymore without offending them?
The beauty of someone's driveway is that you're not "trapped" in their house. You're barely even on their property; and that sidewalk is only a few feet away. When you're ready to leave, just leave (goodbyes are optional). There are far fewer social niceities that need to be observed and worried about when you can literally just walk on down the road.
The driveway is this example is not required; you can achieve the same thing in an apartment complex. But the point remains - lower the barrier to entry as much as possible for people to join your social event, and the chances of them at least trying it go way up.