According to Bioware, one of the reasons Mass Effect became a series was due to the studio's decision to drop development on Jade Empire 2 and go with a new RPG-style series influenced by Star Wars Knights of the Republic.
When Jade Empire was released on the original Xbox, it was met with great reviews and customer support but a lack of sales hurt the chances of a sequel. The success of Star Wars Knights of the Republic made Bioware switch focus from a potential Jade Empire 2 to a new IP which later became Mass Effect.
Since Star Wars KotR ended up becoming very popular with its sci-fi setting and shooting segments, Bioware decided to use that game as the template when designing Mass Effect 1 and the ME series.
If the game was meant to have been completed, original plans were for a release on a trio of platforms (PC, Xbox 360, PS3) instead of just one. The first game was released on the PC but only 2 years after the Xbox game and by then too late to help since Mass Effect 1 was in development.
http://kotaku.com/#!5791912/could-we...de-empire-game