The nice thing about big conferences is that everybody makes an effort to show up. People aren't going to fly in from all around the world to attend a free meetup, whereas they might for a big conference. So the big conferences are really the best chance you're likely to get a large part of the community together for a chat. At the free meetups you'll mostly just be running into the same few people who happen to live less than a 45 minute drive away.

For a 1000 usd conference sure, but it's happening to the grassroots conferences and it's pretty annoying. My suspicion is that it's tied to the current funding craze.