That we are not going to get warp travel, plasma guns, advanced super soldier programs, or any other of the things straight up from HALO that many Mass Effect fanfics give mankind when the don't have Eezo tech...
What we are going to get is being the technologically inferior side in a war and like just like in both Gulf Wars, the Opium Wars, or the Six-Day War, our military is going to get shredded... Which would be bad enough with the Turians, but with fucking Batarians we are going to see many colonies raided and millions of our people enslaved, just to get 5 DP points, which is roughly what we get from a couple of omakes