DaveFlash Why not look at it positively? Apple wants a good experience for their users. So they'd need a financially robust partner with a large support desk. Bunq is simply too small to guarantee a good experience for all Dutch iPhone users.
And Apple Pay is supposed to feel free (or even lucrative, see the new Apple Card.) Given that Bunq Premium costs 8 bucks a month, people would associate Apple Pay with monthly fees.
So there are good reasons for Apple to partner with a big player first. The exclusivity might be required to lure that big player. Dutch banks would much prefer their customers to use their apps.