system
Given the following post, respond as if you're commenting on Reddit:
human
[Mass Effect] Why did the previous cycle only have one civilization while this one has about a dozen?

The Protheans are never mentioned to have contemporaries, despite being more spread out than current galactic civilization. The current cycle, meanwhile, has humans, turians, asari, salarians, krogans, quarians, batarians, vorcha, elcor, volus, hanar, and drell, and probably a few more I'm forgetting.

Is one of these a fluke? What's the norm?

Edit: I've played all 3 games, but without all the expansions (so I haven't talked to Javik).
gpt
I think in ME3 Javik sort of explained it by saying that the Protheans were extremely imperialistic. Therefore, they fought, conquered, and assimilated other races into their empire, and 'Prothean'  became the catch-all designation for their civilization, including the ones they conquered.