Which makes me want to share my new favorite conspiracy theory about the movie(you know a story is good when there are wild theories about an event that was entirely imaginary in the first place, that is a sign of first class world building). anyway,
The entire tesla arc never happened, the whole thing was an elaborate con. "but " you exclaim, "we saw the machine, the hats, the trip to america", to which I reply this is a case of second person narrative the only source for this information is the diary(which the movie dutifully animates) and the diary was planted, the diary was the con.
In the vein of fan theories about imaginary events, a favourite of mine was that James Bond died in Blofeld's brain drill chair and the second half of Spectre was hallucinations as his brain shut down.
The release of a subsequent film with the same actor sadly disproved it.
"basically An Occurrence at Owl Creek Bridge" is a perennial category of fan theory, along with "they were dead/in purgatory/hallucinating in an asylum all along" and "$X is a Time Lord." The latter i've also seen about James Bond.
And of course Nikola Tesla. Which probably makes Edison The Master. There's definitely an AU fan fiction in there somewhere, which in its Golden Age (electropunk?) Lovecraft-noir incorporates "Edison's Conquest of Mars[0]," an influential but otherwise garbage sequel to H.G. Wells' War of the Worlds. Sorry, what was I.. oh yeah. Tunguska. Obviously Tesla accidentally reversed the polarity of the neutron flow.
/s