When you see that Google Drive give you 15GB and the same goes for Onedrive then paying $12/yr for the 15Gb seems strange.
But my grandma/dad who pay have probably never heard to those options and just want their photos backed up. And wouldnt think twice about not using iPad/iPhone or look for stuff beyond whats baked in.
Companies price based on value/positioning. It is naive to think pricing is based primarily on competition. Any book on pricing will tell you that is totally incorrect in the first chapter.
From the Google TOS: "Our automated systems analyze your content (including emails) to provide you personally relevant product features, such as customized search results, tailored advertising, and spam and malware detection. This analysis occurs as the content is sent, received, and when it is stored."
Also: "When you upload, submit, store, send or receive content to or through our Services, you give Google (and those we work with) a worldwide license to use, host, store, reproduce, modify, create derivative works (such as those resulting from translations, adaptations or other changes we make so that your content works better with our Services), communicate, publish, publicly perform, publicly display and distribute such content. The rights you grant in this license are for the limited purpose of operating, promoting, and improving our Services, and to develop new ones."
The above is much, much broader than Apple's TOS.
Google would appear to not just allow ad targeting, but even use of user photographs or videos for promotional ad campaigns on Google's behalf by third parties. I'm happy to be corrected on this, but that is the apparent meaning.
First, you didn't quote this key section of Google's TOS: "You retain ownership of any intellectual property rights that you hold in that content. In short, what belongs to you stays yours." That's a significant limitation.
Second, Apple's TOS is nearly word-for-word identical to the portion you excerpted above:
"By submitting or posting such Content on areas of the Service that are accessible by the public or other users with whom you consent to share such Content, you grant Apple a worldwide, royalty-free, non-exclusive license to use, distribute, reproduce, modify, adapt, publish, translate, publicly perform and publicly display such Content on the Service solely for the purpose for which such Content was submitted or made available, without any compensation or obligation to you" (https://www.apple.com/legal/internet-services/icloud/en/term...)
Third, the general TOS has to be read in concert with the privacy policy and any product-specific privacy/TOS. Those exist for Google+, not sure about photos.
Fourth, there's no evidence Google is doing what you suggest (ad targeting, etc.). What is happening is shared endorsements: https://support.google.com/plus/answer/3403513?hl=en&p=plus_... But note Apple has plenty of leeway to do what it wants: "Apple reserves the right at any time to modify this Agreement and to impose new or additional terms or conditions..."
To actually read and understand a TOS/privacy policy takes some time -- so this isn't a comprehensive response. But maybe it helps...
Apple;
you grant Apple a worldwide, royalty-free, non-exclusive license
to use... on the Service solely for the purpose for which such
Content was submitted or made available
you give Google (and those we work with) a worldwide license to
use... The rights you grant in this license are for the limited
purpose of operating, promoting, and improving our Services, and to
develop new ones.
Everyone reserves the right to modify their agreements, so I think that's a strawman. If and when Apple modifies their ToS to allow them (and those they work with) to use my personal property for promoting, improving, or developing new "Services", then they will have stooped to the same level.
Selling products and services is a lot like real estate, it's sometimes about location, location, location. Google Drive just doesn't compare.