I don't know if this is standard, but at least for some previously enacted electronics regulations I know they look into the real-world effects. I think I was looking for information on how they calculate the battery life for the new smartphone energy labels (e.g. is the browsing test over WiFi or the LTE/NR modem) when I found some document about how much energy they're expecting to save with this regulation. It showed a base path of expected energy consumption development, and then how the regulation is expected to modify that

Edit: not the one I saw before, but found a similar document via https://energy-efficient-products.ec.europa.eu -> policy making -> "EIA reports and related analyses" -> 2025 overview report https://circabc.europa.eu/ui/group/418195ae-4919-45fa-a959-3... -> see e.g. the graphic at the top of page 79

The shaded area is the effect that they think is attributable to regulations, e.g. -2.2TWh electricity per year in the category of phones and tablets when comparing 2010 and 2030

As another example, for "Servers and data storage products" they expect almost no change due to regulation: the consumption is expected to go from 48 to 67 TWh (2010 till 2030) and that it would have been 70 TWh without regulations. If I'm reading it right, this small improvement would be due to the 2019 "information requirement ... including the maximum allowed operating temperature for the equipment ... to stimulate data centres to choose equipment that supports higher operating temperatures, to enable further reduction of the cooling load."

Page 42 shows that they also take into account 'additional acquisition costs' (how much more expensive devices are because of this, I think that means?), but that this added expense is well below the energy costs that would have been incurred otherwise. Of course, that's what I'd say too about my regulations :) but I don't know of another information source for this so this is the best info I have atm