These two videos look identical to me and get the same bitrates. Why are they only uploading in 1080p now though? Their video could be poorly encoded in the first place which YouTube cannot magically save. It's going to look worse in these kind of videos anyway, because of all the foliage and particles from fires.

There is still no hard evidence YouTube made regular 1080p worse to sell "Enhanced Bitrate" and I don't think there is going to be. I think people got used to higher bitrates with 1440p/4K videos and now when they see a 1080p video they are surprised by the quality change, see the "Enhanced bitrate" option and make this assumption.

I have gone back to old videos and they are just the same as they were. They have been transcoded to AV1, but that codec is magic, they are probably using less bitrate now than they were when released.