These are not mutually exclusive statements. It probably can survive for weeks in rare cases, but if it doesn't do that often it doesn't matter.

Any method of transmission that infects fewer than one additional person on average are effectively negligible on the overall exponential curve.

So yes, it is likely possible that symptomatic people can infect others, and it is likely possible that a contaminated doorknob can infect people for a week, but if these things happen rarely enough, it doesn't matter. The virus will die out if other routes of infection (e.g. the more typical person to person transmission) can also be made rare enough.

I see the point you're making from an epidemiological perspective but, because it's so important to people from an individual perspective to avoid contracting the virus, I have to take issue with your claim that it is likely possible to contract the virus from a surface after a period of a week or even weeks. I haven't seen evidence that would substantiate such a claim. According to that preprint linked above, even a period of one week on a steel door handle is more than six half-lives past the "death" of the last detectable viable COVID-19 virus. The science is not all in yet, and it may indeed turn out that COVID-19 is much hardier than we thought, but until then I don't see how you can say that it "probably can" survive for weeks in some cases.

I apologize if this is coming off as pedantic but the damage being done by misinformation and speculation about the coronavirus is significant, and I don't think it's possible to be too zealous about precision here. Trump's claims that fears were overblown and a "hoax" have been amplified into widespread and potentially deadly skepticism that coronavirus is even a danger. People have suggested various quack cures that at best drain the resources of vulnerable people. Even saying something as seemingly-innocuous as "wear a face mask to reduce your risk" ends up having a devastating impact on healthcare providers who really need the masks but can't source them. We should be listening to public health authorities and mainstream health experts, and taking reasonable precautions, but absolutely refraining from speculation that might have unforeseeable consequences.

The relevant part of the CDC quote was "because of poor survivability of these coronaviruses on surfaces, there is likely very low risk of spread from food products or packaging that are shipped over a period of days or weeks" and the study preprint you linked showed that in the worst case (polypropylene surfaces) no live virus at all was detected after 72 hours while on cardboard it was more like a third of that time (with large error bars).