Realize that all the R&D that went into The Order directly translates to shorter development times for any subsequent sequel.
In short, a sequel can be produced in a fraction of the time and a fraction of the budget of the original.
Anything short of a complete commercial disaster, (reviewers won't like their opinions being marginalized, but the final Metacritic average can be ignored) will result in a sequel.
Titanfall and Destiny will also see sequels even though neither really matched the level of anticipation and hype promoting their development and final release.