Even if this is a sweetheart deal every apple device uses an ARM based chip so they are still probably making a tens of millions if not a couple hundred million in royalties from just Apple per year

The question is does Apple want the scrutiny that banks have over them. Part of the article already mentioned that Goldman didn’t like the increased scrutiny that came over their business once they partnered with Apple so I’m sure Apple wouldn’t want the increased scrutiny of becoming a financial institution themselves. Just being the named partner on a card and taking a fee is probably the most they want to do