Lol at the backroom scientists who can, with so much confidence, sit there and state categorically that it's impossible, referencing E=MC2 as irrefutable fact for no reason other than "Just because"
Because you understand the concepts involved, right?
Nobody does, they only theorise them and test them for soundness. Why do you believe you, and the persons you are quoting, are incapable of being wrong about a theory.
E=MC2 is a theory, nothing more. It might never be "broken" in the time of the human race as we currently know it. But for you to sit here now and truly believe that it never will be based on what we believe to be true now then just...well....lol.
You can speculate, but you certainly cannot dictate.