It would be big news, but the same mainstream media that refused to cover the rioting and looting in Philadelphia just before the election, won't cover anything related to voter fraud.
I tend to be more like you on this issue, in that I believe extraordinary claims require extraordinary evidence, or at least some evidence. The key is knowing where to look.
It's a process.
While I'd like to believe at the end of the process, fraud on a grand scale will be found, and Trump will remain president, so far it's not looking like that's the case.
These aren't schoolboys we're dealing with. Your side knows exactly what to do, and how to bury the evidence.