Srinivasa Ramanujan was given a brain, a brain that is not that different from the one we have in between our own ears.
The only difference between Srinivasa Ramanujan and 99.99999% of the human race is that he opted to use his brain power as much as it could be sustained.
If only the rest of 99.99999% of the human population can do the same - becoming a galaxy-roaming race wouldn't stay merely a dream for long.
Our brains may all have the same matter, but that doesn't mean we all have the same abilities or aptitudes. Trust me, I hate the misconception that high level mathematics is accessible only to geniuses, but it's also not as simple as "you can be Gauss if only you try." That's not true. Not everyone can come up with calculus; not everyone can come up with general relativity.
As for Ramanujan, the British mathematician G. H. Hardy, when ranking mathematicians based on talent from 1 to 100 placed himself at 25, David Hilbert at 85, and Ramanujan at 100. To get some perspective, Hilbert was an incredibly influential mathematician who almost beat Einstein to general relativity, and he wasn't even a physicist! That's how talented Ramanujan apparently was. So no, the difference between him and "99.99999% of the human race" is NOT that he "opted to use his brain power as much as it could be sustained."