There are many legitimate reasons why someone might need to make real robocalls. The issue isn’t robocalls in general. It’s unwanted robocalls and scam robocalls. There is no way to tell these apart at the time they’re made. The only thing that can be done is to make identification easier in order to prosecute those who make them.
You need to accept that the telephone network is not, was not, and will never be a privacy-respecting system. Whenever you place a telephone call, your identity is known to your phone company. They know who you called, how long you called them, when you called them, and in all likelihood, what you said. The Government can intercept and record your calls. Your phone by default discloses your identity to the caller. Nothing is end-to-end encrypted. Telephones as a technology date back to before encryption was a thing, and at this point, to turn it into a privacy-respecting system where that privacy is enforced cryptographically or otherwise would result in the need to replace almost every non-cellular telephone in the world (which is a lot!). The best we can do is to forbid eavesdropping, except by law enforcement, and control what can be listened to by law.
If you want to use a privacy-respecting system, look elsewhere. True privacy on the telephone network will never exist, nor anything close to it. The best we can do is take advantage of that lack of privacy for the common good instead of desperately trying to pretend it’s private.