As others have pointed out, lidar doesn't denote capability.

1d lidars that have a range of 8 meters indoors are quite cheap <$15 volume.

"2d" lidar, that is one measuring one plane's depth, are generally a lost more costly. Not only that they are bigger and eat more power. again indoor only.

3d lidars are more expensive still, and if you want it to work outdoors, even more.

Xiaomi vacuum has 1D laser rangefinder that is physically rotated in a 2D plane, much cheaper and simpler than a 3D LiDAR.

Not exactly, as explained by the other commenter, but it could help explain why your $200 Xiaomi has lidar but a $1500 Roomba does not.

You do know that lidar has resolution and a vacuum doesn't need high resolution for its needs vs a car?