Yes, that is exactly how it works. The logic in the article is that the author lost Cantonese because she wasn't speaking it. Atrophied.
The post we're replying to makes a good point. How do you not use the only language your parents speak? It means you're not talking to your parents.
The article admits that she
• rebelled and for a time would not speak (shout) to the parents other than English
• moved to the other side of the continent.
Just so I am clear, you're saying it's not an accepted fact that people don't lose a language they actively speak?
There's a quick summary at https://languageattrition.org/use-or-lose/, from where you can get links to decades of research on language attrition. Apparently, for people who speak multiple languages, there's some kind of interference effect between languages that's very counterintuitive, which means there's not the correlation between time spent per language and fluency that you would think there would be.
Deep enough conversations, periodically, prevent language attrition. How can I convince you? It's really just like anything else: practice helps. Is that a controversial claim?