https://www.sestoshoex.com.au/collections/roller-shoes
Switching from walking to rolling like it was nothing.
I don't think there's a market for this product if you can achieve half of its advantages for a fraction of the price.
"Heelys" were their common name (it's a brand) and they were very popular in the early 2000's. Kids had them everywhere - it was impossible to go to the shops without seeing a kid sliding around.
A comparison to offer though is "why would you pay 10x the price for an electric bike?". I don't think it's an entirely fair analogy (electric bikes let people go farther than they typically could). If you use Heelys, they take a fair bit of effort - it's more comparable to rollerblading. I reckon the Moonwalkers are more 'assisted fast walking' - i can see lot's of middle aged people being more attracted to that than 'roller blading on a budget'.
That said I personally will just continue to walk normally!
I bought a pair when I worked in the SF Armory because it was such a long walk to the bathrooms. Used to get a lot of funny looks from the models.