Board Thread:Questions and Answers/@comment-5441128-20161001192649/@comment-3419253-20161117084759

There was fewer Goa'uld and Ori then the Wraith. Also they where stagnate in population. In fact the Goa'uld themselves where shown in an ep killing their own offspring just so they wouldn't have to share their domains. The Ori also never made more Ori besides Vala's daughter because they also didn't want to share power. So their numbers were limited. The wraith continued to thrive as a species and that's taking in account they already had a ton of numbers on their side even in the Ancient times.

Think of it as an infestation of bugs. On Earth we still have fleas even though we don't want them and try to kill them there still there in hiding and growing. Except with wraith their not just on one planet, there hidden in hibernation in the whole Pegasus Galaxy.