What happened to them is that they are being raced on motocross tracks. It's called sidecarcross! It's a bit of a niche sport; Here are a few pictures of a sidecar built on a Husaberg 650 (which is a completely ludicrous machine in its own right): https://www.facebook.com/dirtyman36/posts/for-sale-vmc-2013-...

Heh, this also seems to have happened to them: https://www.bikeexif.com/ducati-sidecarcross