Go ahead and prove it.
Prior to Einstein coming out with this formula, which I would describe as “A little bit too cute” it was already known that there was an immense amount of energy locked up in the nucleus of atoms. This was no discovery made from extrapolating forward from any magic formulas.
So where is the evidence that this is anything more than a reasonable approximation of what may be exploited?
And this equivalence of energy and matter? Where is that coming from? While there may be great energy to exploit from the nucleus of atoms, where is it shown that mass and energy are equivalent?