I would say that 30 years ago, this was an objective statement of fact.
> He just couldn't imagine any laptop ever being more than a "niche".
And you'll see he was and is correct if you consider, as the author was, the usage model. People largely use modern laptops the same way they use desktop PCs. They simply transport them between their regular workspaces. Multiple devices have been collapsed to one, but the way people use them remains the same.
You are focusing very narrowly on the physical devices that the (then and now) inaccurate label "laptop" has been applied to. The article makes much more sense if you abstract to the concept of a laptop, particularly as pushed by marketers 30 years ago.