Grass-roots opposition to hosting the Olympics led Boston to withdraw its bid for the 2024 Summer Games. (Charles Krupa/AP)

As the International Olympic Committee embarks this week on tours of the two cities competing to host the 2024 Olympics, there’s growing sentiment that a consolation prize will be looming. To the victor: the 2024 Summer Games. And to the runner-up: Wait four years and host the 2028 Olympics.

While the arrangement could be viewed as a testament to the strength of the bids put forth by Los Angeles and Paris, it also reveals a stark reality about hosting an Olympics in the 21st century: Costs are exorbitant, economic benefits are dubious, and fewer and fewer cities bother even throwing their hats in the ring.

Chris Dempsey knows this better than most. He helped create a blueprint of sorts that in relatively short order has invited scrutiny of the process, helping galvanize skeptical populations, prompting cities across the world to pull out of consideration, and forcing the IOC to acknowledge and consider flaws. Thomas Bach, the IOC president, recently said the organization “cannot ignore that we have an issue with the candidature process.”

Just 3½ years ago, Dempsey was debating with buddies whether Boston should pursue the 2024 Games and whether it would actually benefit the city. The Olympics’ recent track record isn’t great: cost overruns, empty stadiums left behind, corruption scandals.

Dempsey helped lead the grass-roots movement No Boston Olympics that prompted the city to pull out of the bidding process for the 2024 Games. He then consulted with similar activists in Hamburg, Rome and Budapest, and those cities also eventually bailed. So pointed are his arguments that he’s also contributed to opposition research. Organizers in Calgary — which hosted the Games in 1988 — considering a bid on the 2026 Winter Games brought him in to hear the concerns and make sure they grasp the opposing viewpoints.

Public support for hosting the 2024 Summer Games in Los Angles remains high. (Lucy Nicholson/Reuters)

“I truly believe the experience in Boston is and should be instructive for people on both sides of the Olympic debate,” said Dempsey, who this month released the book “No Boston Olympics: How and Why Smart Cities Are Passing on the Torch.”

“I like to think that what happened in Boston really has been an example in other cities,” he said. “I think that really there is something to be said for the momentum that Boston created.”

While civic and business leaders prepared Boston’s bid, Dempsey and a couple of friends began studying recent Olympic history and the actual impact left behind for host cities. When the U.S. Olympic Committee decided in January 2015 to put forth Boston as the U.S. candidate best suited to host the 2024 Games, Dempsey said his living-room protest ramped up significantly.

Dempsey became one of the frontmen for the growing opposition, using the platform to highlight his basic thesis about the Olympics: It’s surely lucrative for the IOC but can be disastrous for host cities. While bid organizers tend to paint optimistic projections, No Boston Olympics felt it publicized more realistic and likely outcomes. When Boston ultimately pulled its bid in July 2015 — the USOC selected Los Angeles as a replacement — Dempsey thought his work was done.

Then his phone started ringing. Groups from Hamburg, Rome and Budapest, cities also pursuing the 2024 Games, all had some variation of the same question: How’d you do it?

“I wanted to be helpful in explaining how the IOC process is set up that tends to lead to these really negative outcomes for the host cities,” said Dempsey. “Even though the IOC and its sponsors do great and the TV contracts are profitable, it’s still the case where these host cities have bad outcomes.”

Dempsey began spreading the Boston blueprint. Share the facts. Take advantage of the Internet and social media. Garner media attention. He talked about logos and signs and messaging.

“It was a super-encouraging thing to learn that a small but well-prepared team could pull it off, without having hundreds of thousands of dollars, or a political party behind them,” said Tamás Csillag, one of the Budapest organizers.

The Hungarian opponents collected more than 250,000 signatures and forced a referendum on the issue. Local government leaders were so nervous that they decided to cancel the bid entirely in February, leaving only Paris and Los Angeles in the 2024 race. The IOC will vote to determine the 2024 host in September in Lima, Peru.

When Budapest withdrew its bid, the choice for the 2024 Summer Olympics came down to Paris and Los Angeles. (Benoit Tessier/Reuters)

Calgary’s bid exploration committee invited Dempsey to deliver a presentation in February.

“We’re really committed to hearing all sides of the story. We thought Chris could bring some valuable perspective. He gave an excellent presentation,” said Sean Beardow, a spokesman for Calgary’s bid exploration committee. “It’s been important to Calgary from Day 1 that it’s not just about whether Calgary fits with the Olympics but if the Olympics fits with Calgary.”

While Dempsey and the Boston activists might have created a template for dissent, the LA2024 committee hopes its bid offers a blueprint for other cities moving forward. Its plan calls for no structures that will be built specifically for the Olympics and a $5.3 billion budget that would be significantly lower than the price tags attached to recent Olympic Games. And perhaps key, it has widespread public support.

“Just at every touch point, the community of Los Angeles in the largest possible sense is entirely supportive and embraces the idea of hosting an Olympic Games in 2024,” said Casey Wasserman, the LA 2024 chairman. “That is unique. We are an oasis of optimism.”

Wasserman said the legacy of the successful 1984 Summer Games in Los Angeles has buoyed enthusiasm around the region to play host once again. An independent poll found that 88 percent of Los Angeles residents support the bid; the city council has had 10 votes related to hosting, and all passed unanimously.

While that very well might help Los Angeles secure the 2024 Games — or perhaps the 2028 Olympics — it’s not yet clear whether the lasting impact of this process will be on the bids that cities submit to host an Olympics or the opposition that organizes around them.

While the IOC’s evaluation committee this week tours Los Angeles and then Paris, its ultimate decision could send a lasting message about what a successful bid should look like. Even as the IOC acknowledges the current bidding process might have problems, not everyone is optimistic that the paucity of bidding cities will prompt the organization to make any meaningful changes.

“I don’t see an incentive structure for the IOC to be any different tomorrow or five years from now or 10 years from now than it is today,” Dempsey said. “As long as they have at least one bid, the Games will go on, they’ll still be profitable and still have these lavish events.”