Let nature do its thing and let the virus freely spread. Expect extreme cruelty from a society point of view, all weakest will die without medical care due to health infrastructure overload, with the benefit of very rapid group immunity and this "being over soon".
By that theory, we would have eradicated measles and polio for long.
Herd immunity will never work unless you forcefully contact everyone with the virus.
Whether herd immunity develops depends on how widespread an infection is, and that in turn depends on how good an infection is at spreading itself. There's a minimum level of infectiousness for a disease before it is capable of
naturally generating herd immunity. The 1918 flu epidemic was infectious enough and that's why it eventually died out. Other diseases aren't sufficiently infectious enough for a sufficient proportion of the population to develop active immunity to the same strain in a short enough period of time for herd immunity to naturally occur. We don't yet know for a fact, but it looks like SARS-Covid-2 likely meets the criteria for a virus that would, eventually, trigger herd immunity.
Of course we have an artificial method of inducing herd immunity for many diseases by inoculation with a vaccine. That creates the same active immune response in a large proportion of the population exactly as if we had "forcefully contact[ed] everyone with the virus". This fails to create herd immunity unless a critical portion of the population is inoculated (e.g. outbreaks of measles in modern times as certain individuals have declined to have their children inoculated against measles).
Herd immunity 101 - Just for the benefit of those who don't know what some of us mean by herd immunity.
Herd immunity is where some, but not all, individuals in a population are immune to a disease in a way that effectively protects the whole population from that disease. The idea is that enough individuals have active immunity
* to a specific disease that should a single individual (who is still susceptible to the disease) catch the disease it won't spread. If enough individuals have active immunity then the chance of an infected individual contacting and infecting another susceptible individual before they have either recovered or died from a disease is significantly reduced. It doesn't mean that the disease can't spread at all, but that its chances of spreading are so reduced that only odd individual cases will be seen instead of outbreaks involving many individuals.
*Active immunity (also called specific immunity) - where an individual has either had a disease and recovered, or been vaccinated against the disease so that they have antibodies to the disease, This allows the immune system to immediately recognise a disease and mount a defence to it as soon as the disease organism is encountered. Contrast with passive or non-specific immunity where a disease organism has to be causing problems before the body mounts a defence, by which time it's already a disease in progress. It's like the bouncers on the door of a club having the photo of a troublemaker rather than having to wait for a fight to have broken out (that might spread) before dealing with the troublemaker.