Not too surprising. iRobot was all into SIFT for 15 years before the patent expired in 2020. Meanwhile, Chinese robot vacuums reverse engineered/stole/copy Neato's XV-11 lidar and made it better over the span of a decade (RIP Neato). iRobot joined the lidar party recently but it was too little too late. Product was too expensive and their brand was soured by the poor VSLAM performance. I had one of their mopping robots during the pandemic and you had to keep the lights on to mop. It would often get really lost if it went under a table. I got rid of it and replaced it with a roborock shortly after.
As far as I can tell cheapish 2D lidar for mapping and robot navigation were a bit earlier than the XV-11; they were made by Hokuyo in 2006. I remember that their lidar module was made by some other (American?) company that in turn competed with Hokuyo, people would take them out and use for their own projects.
It's ultimately not very complicated - it's a laser rangefinder that you spin on a motor. It's such a simple - and old! - technology which would obviously get significantly cheaper with time, it was definitely the right horse to bet on. I never understood iRobot's vision strategy.
I think the XV-11 was the first affordable (as in, affordable enough to be part of the COGS and reliable enough to be in a product) for consumers. It helped how there was a cult like following (understandably so) and everything got reversed engineered from schematic to firmware. By principle, a lidar is simple but most things are. The hard part is how to make a product out of it. One of the main things Chinese suppliers improved on 2D LiDAR is having the laser portion completely wireless. Induction powered, and LED light pipe for data communication. This removes the need for the slip ring which wears out and is hard to package.
