One thing to consider is whether the alleged additional energy required for developers to do a leaner job (and as bd139, even that is questionable) would outweigh, or at least be on par, with the cost of software bloat in terms of energy?
There's a big difference between software used by 10 people and software used by a billion people.
That was kind of implied in the following: "the impact of software spreads in very large amounts contrary to that of developers".
Of course if the number of users is not significantly greater than the number of developers, that becomes a particular case and the outcome can be different.
(The beauty of partial quotes =) )
For 10 people it's almost always going to be cheaper to buy them a faster machine. Each. It is at least actually a valid engineering and financial tradeoff.
It also depends on whether the costs of hardware to overcome software bloat are borne by the company itself (e.g. web servers) or by their customers (e.g. Microsoft Windows and Office).
The problem here is that you chose to look at it only from the development cost perspective, which is the most usual way of looking at software bloat (and engineering bloat in general when it applies.)
The interesting point that I found in this thread and which I was embarking on was the energy side of it. Not the development (or more generally "production") cost. The immediate cost is what everyone already knows about. Cost cutting is a cause here, not a consequence. In this thread, I was personally only talking about the consequences, not the causes, as I think the OP was also interested in.
And even the economic point of view is trickier than it appears. People tend to look at economy on very small scales and kinda treat it as though it was some magic. While if you look at the big picture, economy basically follows the rules of physics. Except in very groundbreaking (and now relatively rare) cases of managing to do things much more efficiently without any negative side-effect, whatever cost cutting you're managing to achieve is going to be paid somewhere else.
As to the point about developers favoring code bloat out of laziness and/or because their job is boring, that's fun and rather true in general, but that's again just talking about causes rather than about consequences.
Siwastaja pointed it out: the software industry has been in a deep, ongoing crising for decades now and despite numerous attempts, it's still in crisis.
bd139, working in that area as far as I got, is lucid and honest enough about it all that he recognizes how fucked-up it all is while admitting great money can be made out of it.