“In some future world, maybe not five years, but 15 or 20 years, everyone’s going to be like Harry—nobody’s going to own a car,” Macdonald said in a recent episode of the 20VC podcast with host and entrepreneur Harry Stebbings.

“Nobody’s going to have their driver’s license because you’ll be able to get around. And I think bikes and scooters will be part of that. I think autonomous vehicles will be part of that. I think public transportation will be a big part of that, but I don’t think you need to own a car.”

That future would represent a dramatic shift for a country where car ownership has been synonymous with the American Dream. But with new vehicle prices having soared 30% over the last six years, Macdonald argued that the economics don’t make sense when vehicles spend most of their time sitting unused.

“The individually owned car is the most inefficient asset that anyone owns, and certainly at any level of price point,” Macdonald said. “It sits idle 98% of the day. It’s depreciating. The ongoing operating costs are actually high—even if you’re not driving it, you’re paying for that insurance clip.”

The shift could also prove lucrative for Uber. While the ride-sharing giant abandoned its plans to develop its own fleet of self-driving cars, it has increasingly positioned itself as a platform for autonomous vehicles, partnering with companies including Waymo and Waabi to bring their vehicles onto its network.

Uber’s CEO calls MacDonald an ‘execution machine’—he says these 2 principles drive his success

A Canadian native, Macdonald graduated from the Ivey Business School at Western University in Ontario in 2007 before starting his career as a Bain consultant. He dabbled in entrepreneurship in the early 2010s before joining Uber in 2012. 

Today, Macdonald is the company’s longest-tenured active employee. Stebbings said he recently asked Uber CEO Dara Khosrowshahi, who joined the company in 2017, what makes MacDonald so effective.

“People really like him, but he is an execution machine,” Stebbings recalled Khosrowshahi saying. “And he is very good at driving people.”

MacDonald said there’s ultimately no secret formula for success, but two principles stand out. The first is building trust by making decisions based on what’s best for the company, whether the stakes are big or small.

“You’re not always going to get the decision right,” Macdonald said. “But if people know that you’re filtering on that, then I think that builds followership and trust over time, and then you can move people because if you’re pushing on something, they know it’s because you genuinely think it’s the right thing to do.”

The second is having a deep knowledge of the business. For Macdonald, after 14 years at Uber, he said he knows ride-hailing “better than anyone in the world.”

“Those two things together, I think, are pretty powerful.”

Fortune reached out to Uber for further comment.

AI is already disrupting jobs—and Elon Musk predicts a future where work is optional

MacDonald’s prediction that technology could eventually upend how Americans get around—and even eliminate the need for a driver’s license—isn’t the only eyebrow-raising vision for the future of work and daily life.

The cost of an Uber may matter a lot less if Elon Musk’s predictions come true. The world’s richest man, who has his own ambitious plans for Tesla’s humanoid robots, has argued that saving for retirement could eventually become pointless as AI-driven productivity creates unprecedented abundance.  

“My prediction is that work will be optional. It’ll be like playing sports or a video game or something like that,” Musk said earlier this year at the U.S.-Saudi Investment Forum. “If you want to work, [it’s] the same way you can go to the store and just buy some vegetables, or you can grow vegetables in your backyard. It’s much harder to grow vegetables in your backyard, and some people still do it because they like growing vegetables.”

Khosrowshahi, Uber’s CEO, has offered a similarly ambitious prediction for his own company: a future where human drivers are no longer needed for most trips.

“You can imagine the majority of our trips being fulfilled by robots of some kind,” Uber CEO Dara Khosrowshahi said on The Diary of a CEO podcast earlier this year. “Probably not 10 years from now, but you go 15 to 20 years from now, you’re going to start getting there.”

That future may sound distant, but the disruption is already taking shape as autonomous vehicles roll out in many major cities. Uber is paying drivers to train AI models, while Lyft is paying former drivers to wash autonomous vehicles that have begun replacing some of their rides.