EU rejected that. DMA says that 3rd parties must have the same access to data as Apple does, and obviously Apple does not want to turn Siri into a cookie banner party.
If Apple complied and opened up Siri like the EU wants, the only competition users could choose would be between US companies. DMA does not help EU companies.
There is no one-click way to install an AI model on macOS like potentially iOS could have. I can easily imagine some grandma install on their iPhone some random AI model they saw in an AI-generated Facebook post with just one tap.