Aries - Origin started as the publishing company of Ultima (with #3, iirc). Ergo, Ultima never replaced Wing Commander. It merely shared the spotlight for a while.
Ultima is also one of the most respected names in Computer Role-Playing History, and one of the founders of Origin is probably better known by his alter-ego, Lord British (the name of a ruler in the Ultima games), than he is by his real name, Richard Garriot. The Ultima games were known for a variety of reasons, including excellent plots (ignore the last two games...), and being probably the first CRPG to actual reward the player for making morally based decisions.
Origin was the home of primarily two different franchises - Ultima and Wing Commander - although System Shock was an Origin game that had a sequel released under the EA name, and Crusader was popular enough that it might have become a franchise had EA gone ahead and created Crusader 2.