Imagine software that was delivered 6 months earlier but is 2x slower than it could be. This lead to productivity increase of it's users of 2x during that 6 months. At the expense of some extra electricity use worth $100, they made $10M worth of real world productivity.
My point is... the thing that is much worse than software that is unnecessary slow, is the software that was not yet written at all.
Now ... I think some of the Clean Code ideas are meh. But their performance is not the only or even one of most important aspects of it.
The software is delivered 6 months earlier, and it's 2x slower than it needs to be. Then it continues to get slower, because the company making this code has a culture that actively disdains making software quick (and in any case, the programmers working there don't know how.) 5 years down the line, the software is 2000x slower than it needs to be, and millions of users are having a minute or more of their day wasted, every day, waiting for things to load and icons to move that should be happening in milliseconds. Additionally, the quality and velocity of their work is far lower because using slow interfaces feels like wading through mud, leading to errors and frustration. The total human cost over the next 20 years is on the order of tens to hundreds of thousands of quality-adjusted person-years.
Now, you might say that the right move is to make the code run well once it becomes a problem- but empirically, I don't see this happening!
My point is... the thing that is much worse than software that is unnecessary slow, is the software that was not yet written at all.
Now ... I think some of the Clean Code ideas are meh. But their performance is not the only or even one of most important aspects of it.