I think that is the wrong way to think of it.
Remote work has a short-term advantage in that your workers will be more productive (according to the author) so you'll get more done, and also it is a nice perk to offer recruits.
That sounds like a no-brainer for startups who are thinking about an exit that is a few years away. They don't have to worry as much about attrition, hiring is more focused on senior eng (in my experience), and given the relatively lower cash comp they are trying to find cheap perks.
For the BigCos of the world though, it is different. They have an established business that is probably profitable and they need to cycle in junior engineers and train them to make up for retiring/leaving senior engineers. For them, mentoring is more important than IC productivity.
None of this is to say that the author is wrong, because they are arguing that you can have the best of both worlds by adopting a hybrid mentoring model that they are selling.