Nuance of というので here

Question

Transcribed from podcast about the speaker's three things they want to do before they die. The first example here provides a backstory about their grandmother as to why they want to see the Northern (or Southern) Lights:

これなんでかっていうと、おばあちゃんがね、大好きなおばあちゃんが、ずっと言っていたフレーズで、よくね大学生の時に家に帰って、でおばあちゃんとおじいさんとテレビを見ていると、そうするとね、なんか海外旅行の特集とかで誰かが有名な人がこうオーロラを見に行って「わあ、綺麗」なんていうね。
そういうテレビ番組をよくやっていまして。
そういう番組を見るたびにおばあちゃんが「もう一回人生があるのならば、もう一回人生をやり直せるのであれば、オーロラを見てみたかったなあ」って言ってたんですよ。
これすごくなんか自分的には心苦しいあのフレーズで、なんていうのか、もうその当時たぶんおばあちゃんは七十歳後半で、あまり足もよくなくて、たくさんあるけなかったので、なんか「えー、行こうよ」とも言えなかったし、「大丈夫だよ！行ってきなよ」とも言えなかったし。っていうので、「そうかああー」とかしか言えないんですよ。 なんかあの時に、「僕が代わりに見てくるね」なんて言っても、なんか違うな、別におばあちゃんはハッピーにならないだろうなって思ったり思わなかったり色々なことを考えて、そのコメントを聞くたびに、こういろんな気持ちが心の中にね渦巻いてていったっていうのをよく覚えていって。

My question is how this っていうので should be analyzed.

On one hand, it could be simply be という quoting the previous statement, perhaps being similar to "it's like [the foregoing]" like in this question, with ので just performing it's usual function to mark a reason.

The other interpretation I think of is that this の is standing in for a noun like "situation", so it turns into something like "it being a situation like the foregoing".

What I wonder about is if this interpretation is more likely if there is any difference between this usage and ということで instead. I ask because although a lot of the time they are interchangeable, something tells me の fits better here because perhaps the quoted part feels more personal and includes more actual quotes. I have heard の can sound a bit subjective in comparison to こと so I wonder if something like that is going on here.

I know that it can't be the case that this の always means the same thing as こと used like this, as in this example:

「この花は桜というので、春に咲きます」

...の is standing in for もの, couldn't be こと. But what proceeds っていうので in the transcript here I can only see as a situation the speaker experienced, so こと makes sense to me, but again I have a feeling using ということで here for some reason sounds off.

In case more context is needed/transcription seems off, here is Spotify link: 15:00-16:52

Answer 1

Simplifying the clauses

Looking at the transcripts only, we can simplify the clauses to:

1. my grandma is old and cant walk for long
2. I can only say "oh really"

In which in this case I think it makes more sense that clause 1 is the reason, which explains clause 2.

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Meaning of というので・ことで

Now, compare these:

1. My grandma is old and cant walk for long, so I only reply "oh really" (when she talked about her dream of seeing the Northern lights).
2. My grandma is old and cant walk for long, and I only reply "oh really" (when she talked about her dream of seeing the Northern lights).

I think 1 feels more natural, no? Here, 1 corresponds to your first analysis, which is the same as "ということで", explaining a reason.

The another sentence that you have provided "この花は桜というので、春に咲きます" corresponds to 2, as in "This (flower) is called Sakura, and it blossoms in Spring.". It "being Sakura" is not a reason, the second clause is just additional information.

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Analysis of というので・ことで

I don't think you should over analyse the components. Instead of analysing というので・ことで as という＋ので・ことで, here it is better to just understand that it is used to denote a reason as a whole.

This is because at this point I believe というので・ことで is itself a grammatical component just for denoting reason. In the transcript, the first clause is not a rumor nor heresay that the speaker heard from someone else, but is a fact - the speaker's own past experience. So it will be weird to look it as という, which is used to present a clause you heard from elsewhere.

Compare this with English's "I am going to wash the dishes", "going to" here have no relation with movement at all. You would NOT analyse them as two words "going" and "to", it is just a grammatical component, hence the common shorten form "gonna".

This phenomena is called 文法化 (Wikipedia: Grammaticalisation) and for this specific example on という I found this Japanese article: 「~という」の文法化 逆接表現との共起 by 家田章子, in which you can look at the n-gram analysis at the appendix too. Please, note that the article focuses on というのに instead.