Decent infrared sensors are actually rather expensive. On top of that, the even better ones are under export controls because Russia is so bad at this game that they cannot manufacture their own sensors, thus banning exports actually makes a difference. Many of the intelligent missiles destroying Ukraine have French or other components in them. Same goes for fire control systems in tanks, or goggles used by infantry or pilots.

EDIT: details: https://infraredcameras.com/thermal-camera-export-restrictio...