You can rewind the stream to earlier in the day when the sun is setting, and compare it to now. You can still see ALL the same lights, but they are tiny points of lights now.
Do you people think it's because somehow all the lights in the Vatican are getting tiny amounts of electricity and it's making all the lights really really dim? But no one in Rome is actually talking about it?
Or do you think maybe something is wrong with the camera and it's making things look darker than they should?
(Spoiler: it's the second one)
You can see all the same lights in the stream, they are just super dim. Look at the lights on top of the Basilica. They are still there. No way they'd even be on if there were a blackout. They are just really really dim, because the camera is fucked up.