> What does the iPhone not having space to store all of your photos have to do with using iCloud?

Because iCloud is a big part of their lock-in strategy. The issue is not about transferring a few photos adhoc from a phone. It is about having potentially terabytes of family movies and photos stored and organised on iCloud. Like I said, there is a financial incentive for them to make it difficult for people to move away. There is no easy way to transfer everything off, including all metadata.