Why is there no option to block all calls that have caller ID disabled, or numbers blocked?

I know you can block numbers/callers if the number is displayed in the call registry, or if you have the number in your contacts list. I want to know if there is a reason why Apple did not include the option under Blocked, to 'Block all calls with caller ID disabled'.

After a long google search I found that the only apps that do that, require you to jailbreak your phone.

So my question is: Since it's possible, why isn't it an option in the legitimate iOS?

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