It's only briefly mentioned in the last paragraph of the linked article and also on Apple's website and perhaps somewhat euphemistically mentioned in marketing speak (just like when forced switching to USB-C) so I wanted to elaborate on it a little to give some context:
The crack in Apple's “walled garden” didn't happen entirely voluntarily - the changes were required by a relatively new law, the EU Digital Markets Act (DMA).
The aim of this law is to enable fair competition and reduce market entry barriers. For this purpose, so-called "gatekeepers" were identified that stand out for their strong market position. So far, the EU has named Apple, Alphabet, Amazon, ByteDance, Meta and Microsoft.
For Apple the EU has identified three core platform services :
iOS, Safari Browser and the App Store.
In these services Apple has to open up in the future.
Violations are subject to penalties of up to 10% of the company’s total worldwide annual turnover, or up to 20% in the event of repeated violations.
Apple (and other gatekeepers) is not willingly putting up with this but is taking legal action against it.
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Sidenote: Another current issue that has arisen as a result of the DMA is messenger interoperability
- mainly affecting (regarding market position, not the technical implementation) WhatsApp, Facebook Messenger, and iMessage.