Now that it can in most cases, we don't create an xorg.conf since that would actively make things worse.
you said it yourself: "in most cases". what about the cases, it doesn't? in last week i experienced on two out of three computers that the autodetection fails.
what are people supposed to do?
X dumps a config file to its log (/var/log/Xorg.0.log) when xorg.conf doesn't exist, you can probably copy that and start from there.
the stuff X dumps is rather worthless -- the stanza included in the report's log is not even usably as a starting point.
i am not talking about writing always an xorg.conf but about a well documented way to produce one, when needed.
i don't understand what was wrong with dpkg-reconfigure -phigh xserver-xorgand i certainly don't understand where that blind trust to those automatisms comes from -- everbody sooner or later experiences failing automatisms. why not including a path to get out of the mess an automatism puts you in?