"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.