I am using Motion [0] since years. At least for basic stuff, is easy to configure and very flexible. For more advanced configuration, it required a bit of tuning.
Yes motion is amazing and has been around for a quarter of a century ! very lightweight and reliable.
As far as I know you can do object detection and tracking by gluing it with a yolo model using a few lines of python like this [0].
I saw a bunch of people doing this.
I really wish there was a more unixy tool available in package managers doing this.
Exactly.
Motion can detect objects in the images, but not recognize the object type, but it's easy to integrate with a third party services like the one that you are linking with the scripts features [0].
I have personally integrated with S3 and self-hosted notification to create a small CCTV system, but there is no limit to the imagination of possible integrations.
[0] https://motion-project.github.io/