Except some of their most loyal customers have been switching to other laptops that made less sacrifice. They could have pleased new comers and loyal customers, and kept a better reputation by delivering a higher quality device, instead of becoming just a fashion statement.

They grew because of their obsession with thinness, BUT at some point they should have recognized the diminishing returns, that people wanted battery life and real keyboards. They left money on the table, with regard to opportunity cost, that wont ever be calculatable, by not changing their tune once they became thin enough.

That's one way of looking at it. Another is that they provide products with consistently high margins, and encourage vendor lock in.