Basically here's what he's saying:
"Lucid has only created Dream Drive pro cars until now (AGT and Dream Edition)
It wasn't until they got to models without Dream Drive Pro that they realized that the camera and sensor suite that they need for Highway Assist isn't available in Dream Drive"
That's what I understood from his message. But I don't know, it sounds a little weird too because if Dream Drive is working, you'd know exactly what cameras and sensors that you'd need for it to behave correctly. You shouldn't need to wait until implementation to find out that it won't work lol