Is "topic-comment structure" only used for teaching second language learners Chinese? I personally only knew Topic-comment structure on this site, since it's been used to explain many questions.  I also used it in my answers in the past. Recently, I realized that I wasn't taught this structure in my own school years.  I asked my 中学语文老师 (literature teacher of middle school), who has a bachelor degree of Chinese literature and has been teaching 语文 over 30 years, and she is unaware of the structure too.
A quick Baidu search suggests it's relevant to 对外汉语.
So, is it a newly evolved structure in Chinese literature or used only for 对外汉语?
The reason I ask this is that none of people around me notice this structure except those (like me) who has some experience on teaching/explaining Chinese to second language learners.
A typical example of the topic comment structure: 水果，我最爱吃草莓。In this case, we'd analyze it as : 在水果中，我最爱吃草莓.  So we take 在水果中 or 水果 as adverbial. Well, using topic comment theory, 水果 is topic and 我最爱吃草莓 is comment.  Look like they're different ways to see the grammar per se.
The topic-comment structure 主题述语句式 is a linguistics concept. Also referred to as 主题句 and 主题述题句式.
It appears it has been popularized — in the West — by Thompson and Li, Subject and Topic: A new Typology of Language in the '70s. With that paper, the authors introduce the concept of topic-prominent languages 主题突出语言 (Chinese, Korean, Japanese, etc.) vs. subject-prominent language 主语突出语言 (English, neo-latin languages, etc.).
But there are also Chinese scholars who investigated this around the same time. One of them is Zhao Yuanren 赵元任,《汉语口语语法》（A Grammar of Spoken Chinese):

汉语句子里主语和谓语的语法意义是主题 (topic) 和述语 (comment), 而不是施动者 (actor) 和动作 (action)

So it's definitely not a new idea.
Now, it makes sense that grammar is not taught to natives using linguistics concepts.
The notion is however useful to foreigners, and I would say especially speakers of subject-prominent languages, because it pinpoints immediately the most distinctive trait of Chinese. And it does so in a way that can be understood rather easily, as topic-comment structures exist in English and neolatin languages as well, despite not being very common.
Below, some examples I can come up with, which convey that the topic is especially stressed in the sentence (topics in bold):

[English] it was me who called Anna (= I called Anna)
[Portuguese] à estação, esse autocarro não chega (= esse autocarro não chega à estação)
[Italian] il libro, gliel'ho già restituito (= gli ho già restituito il libro)

(I was also not aware of topic-comment in any of the three above, until when I started studying Chinese)