Yep, this is the open wound in the protocol from the blocksize wars. Weight of witnesses is under-counted compared to normal data. The first two shots broke btcd's witness size limit parameter, which was not in protocol but there because of the likely resource exhaustion attack.

I told y'all that's what they were doing. But everyone wanted to hate on btcd instead of think about why btcd had that limit. Most people probably even think it was a "bug" instead overzealous prudence.

The rewards "curve" also has an impact. Anti-tail-emissions people don't consider the fact that the "increase of supply" is a sawtooth wave with halvenings.