Even with the caveat that they mean only vacuums sold this year the number seems off. There are about 20 million sold each year in the US alone[1]. Assuming 20 times that worldwide, that's 80 million robot vacuum cleaners. If true that's an incredible level of sales for a product that's less than two decades old.

[1] https://business.highbeam.com/industry-reports/equipment/hou...