6 weeks is nowhere near enough, the entire point of lockdown is to prevent further spread and also to wait till the asymptomatic cases are detected and quarantined, a patient could remain asymptomatic for 2 weeks, add to that the time needed to test every single man, woman and child in America (massive testing is needed because it's on a totally different level of spread when compared to China) so I would say minimum 2 months are needed or probably 3 months to completely and utterly end the Covid crisis.
But the thing is in a country as chaotic as the US they probably wouldn't be able to enforce a true complete lockdown for even one week, you will have some states enforcing a complete lockdown while others would only enforce a partial one or may be no lockdown at all, you will have some people abiding by it while others will not.