The "Written Pole Motor" concept has been around for a long time now, it was developed down the road from me at the EPRI (Electric Power Research Institute) in conjunction with a company in Florida called Precise Power. I don't know who this other company is in that link, likely a knock-off or spin off, but Precise Power owns a trade mark on the term "Written Pole" and this other outfit uses that term, so if it's not a collaboration, it's a lawsuit waiting to happen...
If you are interested in learning more, here's a slide show presentation on the technology done by a PE from from the EPRI, Lee Layton.
https://pdhonline.com/courses/e299/e299content.pdf
I've seen them in operation at a demo at the EPRI maybe a decade ago or so, they work fine, but yes, they are much bigger than the same HP rating in 3 phase, and they are EXTREMELY expensive. But in many of our (North American) far flung rural places, the utilities will not run 3 phase power at all; they will run single phase, even if it is for large motors. So this is actually a viable solution in those cases. I had no idea the market could support TWO manufacturers though...