I don't think value can be determined by production cost. I could spend the rest of my life and energy polishing a turd. That doesn't make the turd valuable. On the other hand, someone might make a piece of art with a canvas, some paint and a day's worth of effort that sells for millions. Clearly not what it cost to produce. Value is subjective and does not exist outside the consciousness that thinks of it.

Sounds a lot like Marx's labour theory of value

Why would you be only 60% confident? To me that sounds like a clear answer that the base layer won't need to change, and hence won't change for Taro.

Apparently that's most likely a mistake of the current draft of the BIPs, so there shouldn't be any L1 changes.

See: https://reddit.com/r/Bitcoin/comments/twx8ui/announcing_taro_a_new_protocol_for_multiasset/i3j6ffr?context=3