我(Wo, "I") has been constantly used for a very very long time. Just less in poetry. For example, this is from early 19th century[0]:
>> 嫣娘答應著,出來三步兩步,連忙跑到園裡,一進門就高聲說道:「我回來了,我可也回來了!」
This is from Journey to The West, 16th century:
>> 我等在此,恐作耍成真,或驚動人王,或有禽王、獸王認此犯頭,說我們操兵造反,興師來相殺,汝等都是竹竿木刀,如何對敵?須得鋒利劍戟方可。如今奈何?
This is allegedly more than 2,000 years(!) old[1]:
>> 帝力於我何有哉
Actually, there are pronouns specifically created for western text:
- 她 (she)
- 妳 (female you, no longer used in mainland China)
- 祂 (originally this character was only used for He and Him in the Bible).
The author mentioning 我 instead of these makes me question how knowledgeable this article is.
[0]: https://zh.wikisource.org/zh-hant/%E9%A2%A8%E6%9C%88%E9%91%9...
[1]: https://zh.wikisource.org/zh-hant/%E6%93%8A%E5%A3%A4%E6%AD%8...