1. I think this will not change anything to the people vested in the Apple only software and digital services.
2. The main difference might be for new device owners. It will be easier for them to use on their device the services they are used to or want.
3. I believe that Apple has been ill advised all the way. I believe that Apple could have maintained the App Store has the sole software distribution and install mechanism on iOS if it followed a non invasive approach to user properties (businesses and people), their safety, privacy and security. Paving the way for a different approach to app distribution on specific kinds of devices.
Make no mistake, an App is not just an app, it's a surrogate of a business. An App is not just an App, its tool used by a person to achieve a particular task. An smartphone is not just a smartphone, is a component of a wider digital network, the Internet that is also a component of a region communication platform and infrastructure.
The EU and its members have total democratic political and legal legitimacy to regulate the components of the Internet infrastructure in their regions and its suppliers. Wall gardens specific in nature within it are acceptable, but not fiefdoms controlling the border between people/businesses, the Internet, and other people/businesses on the other side of the line.
A border that is composed by internet connected devices and internet connections, as you guys know. The iPhone/iOS is one of those devices, so is your internet connection of choice. The border components are in principle suppose to be Net Neutral in they way they work and how OEM and service providers operate them.
Has someone might have said, who controls the borders runs the region, case in case the digital market on top of the Internet within the EU. For that matter, border control is not an asset to be exploited by private businesses of any kind. In others words, businesses may try, yet such objective is not legit in a Democracy, no matter the percentage of the border they might already control. The mechanisms used to achieve such control end up being dismantled one way or the other.
Well, unless they aren't. But then we would enter into a new global order of things. Who knows if that will happen. Yet I wonder how many people are willing to fight for such an order. Because history has shown that such changes require a lot more than a wallets.
EDIT: I personally think that Messaging and Call consoles are an intrinsic part of what makes a phone a phone. Much like the ability to install Apps is what makes a modern computing device. In that mater I believe requiring these consoles to be swappable may be a step to far from the regulation ... In other words regulators should instead think on what are the primal components that make such a device let it be an OEM thing. Yet the reality is that not the issue they seam to be addressing, is mostly a side effect of internet connected devices OEMs push back on regulation in the last decade.
Cheers.