I think he was talking about entering legally but overstaying. If you are accumulating illegal presence, but have a legal way to adjust status, then you'd be well advised to apply from within the US. If you didn't enter legal, you can't adjust status here, and when you do leave (or are forced to leave), you may find yourself barred for attempting to return.
Citizenship isn't going to happen unless you have permanent residence, no matter long you are here, legally or not.
Permanent residence is not granted just because you ask for it, no matter how you enter.
This appears to be a hypothetical issue, but to answer your question, you don't get any preference for being here other than they won't deport you while a legitimate change of status is in progress. Anybody trying to enter the US (or adjust status to remain),had best run the details by competent counsel (i.e., an attorney).