Billionaire Mark Cuban has emerged as one of the most prominent critics of humanoid robots for consumer households, repeating his criticism on Monday after previously predicting both robots and their manufacturers would “fail miserably” within five to ten years—contradicting the bets placed on the technology from other billionaires like Elon Musk.

In an appearance on tech livestream show TBPN in March, Cuban first predicted a 5-10 year lifespan for both humanoid robots and their manufacturers, adding household robots would take more optimal shapes designed for their specific tasks.

Cuban doubled down on that prediction on Monday in a post on X , noting that humanoid robots are large in size and difficult to make for multiple functions.

“Would you rather have a roomba or a humanoid that pushes around a vacuum cleaner or broom?” Cuban asked.

Earlier this year, the billionaire investor predicted humanoid robots would be “great novelties,” but ultimately would have a lot of major issues—including having to be “upgraded continuously.”

“Everybody defaults to, ‘well we live in a human world, and humanoids will take the place for humans in various functions, particularly in the home.’ And I think there’s just no chance,” Cuban told TBPN in March. “I think if you look at warehouses and what Amazon does—they’re not humanoid robots carrying boxes. They’re robots that are designed to fit the environment.” Cuban predicted that houses would be “redesigned completely” for robots. In his post on Monday, Cuban compared this to how house designs changed in the past few centuries to make room for now-standard appliances like refrigerators and dishwashers. As an example of what an optimized robot could look like, Cuban said they could resemble spiders or ants with hands for “the ability to carry and lift things.”

Cuban’s prediction stands in stark contrast to predictions about the technology from some other billionaire tech investors. Musk, the CEO of Tesla, has long promoted the idea of shipping humanoid robots to consumers and has moved to reorient his company to focus on robotics. “I think Optimus will be not just Tesla’s biggest product ever, but probably the biggest product ever,” Musk said at Tesla’s first quarter earnings call in April. Part of Musk’s staggering $1 trillion pay package from the company is tied to delivering 1 million robots, likely referring to the company’s Optimus robots. Tesla said it was ending production of several electric vehicle models at its factory in California to manufacture Optimus robots. Tesla is now producing hundreds of robots per week at the facility, according to a report from The Information , but that’s far from its stated goal of manufacturing one million robots per year. The company has hit production snags, including assembling their robots’ hands. Other humanoid robot manufacturers have seen major interest from investors this year. Chinese robotics firm Unitree went public with a blockbuster IPO in August, which saw the company’s share price rise 460% and raise roughly $905 million. Agility Robotics also plans to go public by merging with a SPAC in a $2.5 billion deal, the company announced in June.

We estimate Mark Cuban’s net worth at $6.8 billion, making him the 597th wealthiest person in the world as of Tuesday. Cuban was the former owner of the Dallas Mavericks, and famous as one of the investors on CNBC’s “Shark Tank” reality program. Musk is the wealthiest person in the world, and his current net worth is estimated at $908.5 billion.