It is possible that Mobileye could have a secret deal that they have not announced yet. Also, Mobileye says that their goal is to make SuperVision and Chauffeur a "turn key" solution, meaning all the hardware and software would be done for the OEM. The OEM would just "plug and play" so to speak. Also, Mobileye could do geofenced robotaxis in the US first before making a deal with an OEM.
Obviously, I am speculating since Mobileye has not announced any concrete US plans yet. But considering all the mapping and testing, Mobileye has done in the US, it only stands to reason that Mobileye intends to release SuperVision and Chauffeur in the US at some point.