In 2014 it was Michelin and BMW that were going to bring us airless tires. In 2019 it was Michelin and GM. And in 2024 as of this week, it's Michelin and Tesla.
I will say that airless tires have made their way first to skid steers, then to fork trucks, and then to commercial grade zero turn mowers (and I'm sure in other types of lawn care or construction type vehicles). So there has been movement in this area, but certain issues still persist.
First, the lack of a sidewall. Snow, mud, ice? Do those things not exist in the airless tire world? Not an issue on slow speed vehicles, but even a slight imbalance at highway speeds is a big issue.
Second, pneumatic tires can adjust by adding or subtracting mass (air) as temps rise and fall. But when you replace the air with some kind of rubber compound that hardens and softens with temperature, how do you adjust? Again, not really an issue on slow moving vehicles as you can just pick a decent middle ground, but a big issue on fast moving cars.
Third, and really what is the biggest issue, is this quote from 5 years ago in Torque News: Imagine a Michelin man walking into a boardroom and announcing "Great news! We just found a great way to sell fewer tires and make less money!"
So good luck to Tesla if they've decided to give Michelin more money to develop a tire they have no desire to see come to fruition.