Bill Barhydt, founder and chief executive officer of Abra, speaks during the Consensus: Invest event in New York, U.S., on Tuesday, Nov. 28, 2017.

Cryptocurrency conferences are still a massive business, even if bitcoin's price has plunged this year.

When it kicks off this week, one ticket to CoinDesk's Consensus three-day conference in New York City can cost roughly $2,000. Well over 4,000 are expected to attend, up from 2,700 attendees last year. So at a minimum, the conference is likely bringing in $8 million.

More than 20 other events, some with similarly high entrance fees, are also scheduled during the days around Consensus. The bitcoin conference that began with 400 attendees three years ago is now the centerpiece of a full-blown "Blockchain Week NYC," an event run in partnership with the New York Economic Development Corporation.

Consensus conference attendance growth over the years

Source: CoinDesk

Last year's conferences helped drive the surge of attention on cryptocurrencies.

Around Consensus 2017 last May, Bitcoin accelerated its gains above $2,000, and was bolstered by the first TokenSummit and Ethereal Summit.

Prices then skyrocketed over the rest of the year, drawing Wall Street's interest and topping $10,000 for the first time after the "Consensus Invest" conference in November. Since then, however, Bitcoin has lost more than half its value since topping $19,000 in December, but it remains more than 4 times above where it was last May.

This year's speaker lineup also reflects significant inroads made by the cryptocurrency industry into the mainstream. Twitter co-founder Jack Dorsey, whose mobile payments company Square launched bitcoin trading this year, is set to speak at Consensus on Wednesday. Other conference panelists range from government officials to start-up leaders.

Consensus "does have a reputation of, if you speak at that event you're on the map," said Michael Oved, co-founder of a token marketplace called AirSwap, and organizer of a blockchain conference called Fluidity, which took place Thursday.

He said he purposely under-priced his conference – tickets ran from $150 to $250 – because he saw it as "an opportunity for us to talk about the things we've been working on." About 700 people attended the Brooklyn event, Oved said. That would bring ticket sales to about $140,000.