Covid-19, herd immunity and common sense

There has been a LOT of talk in the media, various forums, twitter, etc, about "herd immunity" in regards to the corona virus pandemic.

The idea, basically, is that if enough people catch and subsequently become immune to the virus, the virus will "look around" for new hosts within the population, as some have suggested, and finding none available, recede and eventually die out.

That "looking around" suggests viruses are alive, seeking to reproduce like bacteria and fungi.