Columnist: The relief from the drudgery of physical labor that much modern technology affords its users renders them dependent on this technology, and, more importantly, on the elaborate energy systems required to run it.
Conclusion (clearly, then)
In addition to undermining life's charm, much modern technology diminishes the overall well-being of its users.
Evidence
Modern technology provides relief from the drudgery of physical labor, but it makes its users more dependent on this technology and on the elaborate energy systems required to run it.
Evaluate
There are two new terms in the conclusion, "undermining life's charm", and "diminishing the overall well-being of its users".
The author must be assuming stuff in relation to both phrases. Did the evidence talk about anything like "undermining life's charm"?
Not really. We know that modern technology relieves us from the drudgery of physical labor. Was the author assuming that ? Maybe.
But we should also consider the possibility that the phrase "in addition to undermining life's charm" is a random aside. It's not part of the main clause of the conclusion, and it's the main clause that the author is concluding.
Did the evidence talk about "diminishing the overall well-being of its users"? The closest match would be the one negative thing we heard, which was that modern technology makes its users more dependent on technology and the energy systems that run it.
So the author seems to have a Linking assumption that .
We've covered Links. What about Objections? How could we accept the evidence but argue that almost all modern technology improves / maintains the well-being of its users?
We could argue in a Net Gain / Loss style that even though modern technology has the negative of making us more dependent on tech / energy systems, it has positives that offset or outweigh that negative.
Goal
Look for a Linking assumption connecting "more dependence on tech / energy systems" with "diminishes overall well-being".
Or look for a Defender assumption saying,