Yes that article is an old one and is American, but the part I was referring to (Supporting 95% of their portfolio) is unlikely to have changed since then, and that stipulation will almost have certainly crossed the pond.
As far as Apple is concerned this makes real sense. once a bank supports Apple pay they get listed on this page:
Which might at first seem insignificant and trivial, but having your bank on there while a good percentage of customers can’t use the service will not just result in a banks customer service getting a battering, but also Apples customer service too.
Google Pay on the other hand clearly doesn’t have this rule, and instead just has a column for ‘unsupported cards’:
https://support.google.com/pay/answer/7351534
My guess here though is that this is because Google, unlike Apple, is unable to lock down NFC chips, and therefore Google Pay will certify any bank, no matter how many cards are supported by them, just because they are so desperate to avoid what Barclays has done on Android which is bypass Google Pay entirely and integrate mobile payments into their own app.