I'm not convinced that it is. Sure, election rigging happens, but that's not the “getting away with it” that would be at issue. Either people who get away with it undetected in the very short term are so good that they manage to suppress all evidence completely and it never comes out (which seems an implausible binodality in outcomes), or it usually is quite evident in even the very short-term, and either fails to do enough to change results, does enough to change results but is corrected by institutional processes, or it does enough to change results and is allowed to stand by corrupt institutions despite being widely decried.
There's not a whole lot of modern cases where election fraud is discovered only long-after the event rather than virtually in real-time.
Is vote rigging and conspiracy to rig votes possible in the modern world? Yes. Is it ever both significant and not immediately evident? It's not impossible, but it doesn't seem to be the case. If it were, you'd expect there to be examples of cases undetectable in the short-run but later discovered.