Let’s go down C.
If your financial info is on someone else phone you have other issues. That is on you. So not valid.
Your contacts being snoop up. Again you gave the other person your contact info. Plus plenty of easier ways to scoop it up already in use and chances are good that already been shared and access.
Any messages you sent to another person it is already outside your control.
If anything it would force Apple to increase security and privacy even more and make it harder for apps to break out of the sandbox. Also could encrypt the raw data even more so it can not be scooped up.
Your C is mostly just excuses to cover up your own bad security behavior.
Way to assume and over generalize. I assume you are not married or for other reasons have a shared bank account. There are many reasons to have some level of financial entanglement with another individual or business.
But, nice of you to assume I have no concept of financial or data security.
Texts I may have sent to another are open to be forwarded, true. But an unscrupulous app could quite easily sniff all messaging apps on the phone - including all history. That is a little difffernet that someone I message forward a text or two.
And the fact I gave my contact info to someone does not mean I (or they) are granting access for it to be disseminated to the world. And people do add notes or comments to contacts beyond what I shared in the first place.
Finally, I did say that my comment did lean a little tin-foil-hat side. Is it likely all my hypotheticals occur? No. Is it possible, sure. It is.