Another reason why that synchronous 14 day lockdown would fail to eradicate the virus: unless you are going for total solitary confinement, intra-family transmission chains would be able to sustain the virus much, much longer than those 14 days. Even a household as small as a two child nuclear family could sustain the virus quite long if each infection happens to have a fan-out of one and happens rather late in the contagiousness window.