As Lab Guy noted, we're externalizing a lot of the real costs. In order to understand the FULL costs (environment- bean-counting is always done using cups [and the "shareholders" will be sure to hide stuff in order to ensure they get a larger chunk out of the worker's toils]) you have to start from the very ground up. How much energy went into all those man-hours to design and build those emissions systems/components [be sure to include housing and travel costs!]? How much cost is there in replacement parts (have to have an idea of replacement interval- <- this is perhaps the core of this discussion [if things lasted "forever" then there really wouldn't be a concern])? DEF containers and on and on. Many people will latch on to these things to flog folks who may be supportive of emissions "solutions." There's something to this, but then again we cannot KNOW for certain unless there's a full accounting. And anyone who is being honest will accept that we have allowed ourselves to self-deceive by externalizing costs: lots in the form of environmental costs- look up Steve Donzinger for a story concerning things of this nature; CoyPatton noted this same kind of issue (one that I KNOW of and speak of when possible); note that these two are energy-related issues- this should trigger a bit of deeper thing in people about what is really going on.
Newer engines ARE more efficient, but not because of the emissions stuff. They're more efficient because of better materials and better manufacturing, both allow achieving better tolerances. Add in computer controls and things are a lot more efficient. Emissions "mandates" have given an extra push towards increased efficiency because cleaner burns mean getting more power from input energy (we're talking ICEs and diesel/gasoline here).
We won't be able to save the planet by having everyone driving EVs or operating newer tractors (in another thread I voiced by opinion as to what I think is the probability of seeing EV CUTs [spoiler alert: pretty much NILL]). We can't use "efficiency" to "save" us. The reason can be found via Jevons Paradox: briefly stated as "efficiency" meaning an improved rate of depletion of natural resources. All living things on the planet have an observable check on their populations; humans have an awareness of what our is [ourselves, and our habitat/environment]). Growth (almost always stated as good, and mostly about "economic" growth) is based on increased consumption. Our game is "growth," without us really understanding that perpetual growth on a finite planet isn't possible: the game WILL end, either through environmental collapse [hitting nature's wall] or via collective suicide [nuclear war].
As to affecting "economics," all I can do is laugh. When our "economics" is based on the notion of perpetual growth on a finite planet I have to ask why people feel the need to champion/defend this as being something good. Good for the System, OK, but what is that System doing? Read up on Steven Donziger. I'll jump off the podium by stating that profit-taking by the handful of big shareholders does more to increase end-user costs than does environmental/emission related stuff. (no matter what profit levels or profit sharing, or not, as long as we're playing the game of perpetual-growth-on-a-finite-planet we WILL [mathematical certainty] ALL come up on the losing end [to mother nature- "nature bats last!"]. Human hubris is everywhere present and pervasive.
Disclaimer: I have OLD and NEW diesels; each has their place and their reason for being my selection; I view each as having their own positives and negatives and I adjust accordingly [everyone does, until it's no longer possible- all will eventually turn to dust]. I do not claim to KNOW any "solution" (the very word denotes a permanent state, and as long as time clicks by there is no such thing as permanence), nor do I evangelize FOR or against emissions stuff (or saving the planet/climate, though I DO value having a livable environment [I can, however, state that a LOT of people and a LOT of old diesels isn't a pleasant mix- go visit Manila to understand]).
