Videogames aren't more popular than Movies or Television. It is true that the gaming industry profits more. That doesn't mean people play as much videogames as they watch TV or go to the cinema. It just means games are more expensive and attract people with slightly higher acquisitive power.
Besides, Mass Effect never had massive sales like other videogame franchises. It's something tailored for aficionados of Action RPGs. The "Average Joe" doesn't know anything about ME. And I really doubt gamers who use consoles primarily as "COD/FIFA Machines" really know much about stuff like ME. Star Trek, on the other hand, is a Pop Culture icon that almost everybody knows about, for decades. Even if you aren't into it, you probably are familiar with elements like Spock, the Enterprise, etc. ME sounds very niche when compared to ST.
I'm not saying that ME or Babylon 5 plagiarized Trek, however, if you're doing a Space Opera with interspecies diplomacy elements, it's quite certain you were influenced by Trek somehow. The aesthetic may have been influenced by other materials, but ME's ethos is very Trek-ish.