They exist exactly and only to make the user experience of their devices better. They don't make sense outside the Apple ecosystem, and that's how I imagine it's intended to be.
I have a mac and an iPhone and an iPad and I just want to be able to text my wife on any of them and have it work. That means contacts need to be synced, and there needs to be an answer for how the messages are synced between devices. Same with notes/calendars/etc. iCloud is hiding beneath all of it, and the whole point is that you don't see it, you just see your contacts list works everywhere you look.
The alternatives do lack a number of features.
If they are going to improve integration with third party services, I would love to have better integration with Google’s services, not IBM’s..
I think it's a good move. At the very least, they can learn a bit from someone else on how to run a cloud service.
Let me ask you this -- if you didn't already have the Apple hardware that was integrated with iCloud et al, would you pay money to use any of the Apple internet services? Like if they build Windows clients and you had Windows, would you pay to use any of their services?
I can't think of a single Apple service I would pay for if I wasn't on Apple hardware. And even worse, despite the free services from Apple, I will pay to use competitors that offer a worse integration, just to not use the Apple services.