Ways to not reach me

I’ve implemented a very strict policy for inbound phone calls. If I don’t recognize the number it goes to voicemail. If its important enough to call me, its important enough to leave me a message.
If a call comes in with an unknown number, I won’t answer it. It can go through to voicemail. If it comes through with a restricted number, it only goes through to voicemail, though I am starting to think that such calls should be automatically blocked (as in never even given the opportunity to go to voicemail).
Why have I implemented this policy?
It seems there is a very large collection of people who believe that mass cold calling and using my very precious time before I tell them “no” (which I always do) is somehow a good thing. If I fielded every call that came in (I used to), then I’d be on the phone for hours with people whom are trying to sell me crap.
These days, I’ve noticed in my very limited set of calls I answered with numbers I didn’t recognize before answering, that the caller is not even human. Robo calls. Once I hear this, immediate hang up. If they can’t be bothered to employ a human being to make their annoying calls, I can’t be bothered to listen to their message.
I have to say though, my life is improved since I’ve implemented this policy. My hope is that others also implement it, so we can defeat a business model that is simply annoying, by making it completely unprofitable.