not only… but also
let alone
of course
Structure
- Noun + はもとより + Phrase
- Verb + の/こと + はもとより + Phrase
硬
[AはもとよりBも - A is natural/obvious, and by the same logic, B is also true]
[More formal ‘not only, but also’ pattern than だけでなくand はもちろん]
最近ではコンピューターやスマホはもとより、歯ブラシさえWIFIを備えている。
By what logic would it be natural/obvious that because computers and smartphones are equipped with Wi-Fi that a toothbrush would be, too? 
I’m not asking to be a smart-aleck. I’m asking to be sure I understand the use of tihs grammar point. Is this example sentence perhaps tongue-in-cheek?
I think it makes sense if this sentence was from an article talking about how everything these days is equipped with Wi-Fi. So, of course computers and smartphones have Wi-Fi, but not only that, toothbrushes have Wi-Fi too.
– Lately, not only computers and smartphones [naturally/obviously have Wi-Fi], but also toothbrushes are equipped with Wi-Fi.
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Sure, that could make sense. I guess that would make this not the best example sentence if it was isolated from context that’s important to demonstrating the nuance of the grammar, though.
Edited after further reflection
You know, it just occurred to me that the article context doesn’t really fit, either. That would be breaking the relationship between A and B that’s stated in the grammar point description.
[AはもとよりBも - A is natural/obvious, and by the same logic, B is also true]
Unless this nuance is worded in a more restrictive way than is intended, or unless this pattern has broader usage than just what’s given here (which very well could be true, as other grammar points do), you would need to state something about everything being equipped with Wi-Fi before はもとより. The “same logic” is supposed to connect the two clauses, not merely join the sentence into a broader context.
Maybe I’m just getting too hung up on the nuance?
How about this…
A はもとより B も X。
To make it fit this example, I’ll move some letters around…
A + B はもとより C も X。
A and B have property X.
C also has property X.
Everyone expects A and B to have property X. It’s natural.
But more than (より) that base (もと) expectation, it’s surprising that C has property X, and for the same reasons that A and B have property X.
Not only A and B [have property X], but also C has property X.
A = コンピューター
B = スマホ
C = 歯ブラシ
X = WIFIを備えている
A や B はもとより、C さえ X。
コンピューター や スマホ はもとより、歯ブラシ さえ WIFIを備えている。
It’s a more colorful way to describe the factual sentence:
コンピューター や スマホ や 歯ブラシ は WIFIを備えている。
I think you’re getting stuck on the words “same logic”. Maybe instead use “same feeling” or “similar manner” or “in the same way”?
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Thanks again for your reply!
That definitely fits the sense of the example sentence better. You’re right, I was getting stuck on the words “same logic,” but I might suggest those are the wrong words, based on what you’ve provided. “‘Same feeling’ or ‘similar manner’ or ‘in the same way,’” appear to better fit the example sentence. The thing is, those are largely subjective (perhaps except for “similar manner”), whereas “same logic” is mostly objective.
Is it the case this grammar point is used for both objective and subjective inferences? I ask because the distinction is emphasized in other grammar points, whereas it’s not entirely clear for this one.
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Err… You’ve reached the extent of my knowledge. 
@mrnoone Would you care to weigh in on this discussion?
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Ha, no worries! 
I appreciate the helpful feedback thus far.
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