So to clarify–your understanding of the article is that, it says that a product engineer should be working at an expert level (or at least same level as full-timers of those roles) in about 10 different roles in addition to developer? And they should be doing this during 8 hours of every single day, context switching between different roles in small time slices?

If the above is your understanding of the article, then I'm sorry to say, you seriously need to work on your basic reading comprehension skills.

And if you actually understood the real point of the article, that all of the described activities happen spread out over longer periods of time, as the engineers build up a momentum of total product/business knowledge/expertise/rapport with other stakeholders in the org, by actually being curious, asking questions, and offering measured feedback; if you really understood this, then seriously, I have to question why even bother to reply and waste everyone's time? Totally pointless.