re: asymptomatic spreaders.
Yes, but the way viruses work and survive is by causing their hosts to spread them. And the most common ways are things like coughing, sneezing, puking, and other uncontrollable body fluid discharges.
If you are asymptomatic, then you are also not spreading - at least not in any efficient manner.
Is an asymptomatic person less contagious than a person with the full on virus? I would think so. Especially if the person’s immune system has fought off the virus.