"Busting her ass at Apple for 6 years might set up a young designer to get taken very seriously if she decides to move to another company, or start her own."

No. Don't take a job under the premise that it has good experience and will set you up for a later higher paying job with another company. That's a a myth. Get better at negotiating your salary now.

You should never take the mindset to to defer your salary in exchange for experience. Get paid what you're worth.

I think the argument is that a job is more than just about salary, as long as you're getting paid enough to live comfortably, because there's more to job satisfaction than your paycheque. In the case of Apple, that comes in the form of working in a good (pro-design) environment, on a good design team, on projects that people actually use. On top of that, you're working for a famous company on highly visible products, which is an additional bonus on top of the rest of the job.

I certainly would never tell someone to take a crappy job because of visibility, but if you're getting paid enough, then highly visible work is a 'nice to have'.

You're creating a false dichotomy. One can be good at negotiating salary and still choose a job that comes with high demands.

It's obviously not a myth that each job can help you get the next. Else why does anyone prepare a resume? Or do an internship?