Agreed in a theoretical sense, but how would you handle the physically small icons where removing some of the content is needed (like some of the examples in the article)? Our eyes can only see so small, even if in perfect detail (think about the small print on chargers).
The problem with this is that you then have to drive that 8k, or multiple 8k, monitors which is a problem if you're doing anything visually complex. As someone who straddles the programming / visual arts world (I write plugins for 3D modelling software) I actually spend most of my time having to use "low resolution" (1080p or 1440p) because I'm dealing with complex polygon models with tens of millions of polys and scenes with sometimes thousands of objects in them. You get a similar problem with games or doing video editing. It also doesn't address the problem that there's a limit to people's visual acuity (especially as they get older as I'm rapidly discovering at 40) so you still have to make icons "bolder" and change details as the article addresses as they get smaller to make them more "readable".
The tradeoff between a little bit or human touch and effort upfront vs higher energy and CO2 expenditure overall is not something I find personally compelling
Higher resolution monitors do not necessarily draw much more power! Most of the energy goes into the backlight, which is largely constant irrespective of the resolution of the LCD panel in front. Similarly with OLED, the power consumed is mostly a function of the total lumens the panel puts out, not the size of the individual pixels.
You'd need more powerful video cards, sure, but for typical 2D graphics, the difference is on the order of 5-10W, which isn't exactly going to boil the oceans...
