Just to help clarify -
The workshop in 2.0 does not save you 1 gold, it saves you 2 silver as your 20 ranks generate 100 PP which you pay 80cp for, the workshop doubles your potential capacity before batch making your 20 ranks generate 200pp which you pay 160cp for (a total of 4 silver saved per LP, but only 2 of those are from the workshop). At this rate if you were purely producing and merchanting without batching you would recoup your Workshop in 25LP. While your discount does extend into your batching the fact that the second 200pp will cost you 320cp doesn't actually "save" you 80cp, it costs you an extra 120cp from base.
In 2.1 the 10pp bonus you would get from a workshop (if directly merchanted) equals 5 silver a day or 20LP to pay off, and each additional batch made is made at cost (assuming you spend into CAE). Your second batch of up to 10pp costs you 100cp worth of materials, while your 3rd and 4th batch also cost you 100cp worth of materials each.
So, I believe the core issue is the valuation of the 2.0 workshop and how you are calculating the "savings" from it. The 2.1 workshop is much more efficient, and even more so once you place a Workshop of Convenience Ritual on it (the best 2.1 ritual in the game in my opinion haha)