I was a little surprised Kentaro didn't even consider the idea of them having ended up in the Hollow Earth, and just took Tim and Verdugo's word that they were dead.
I don't think Kentaro even knows about the Hollow Earth, does he? It's a long-discredited theory at this point; even Monarch treats it as unconfirmed in KOTM in 2018, three years after this. And Hiroshi in 1982 dismissed Bill Randa's theories as crackpot stuff. So what happened back in 1962 must have been classified.
Well, if my memory isn't letting me down, wasn't Monarch basically a sad shell of itself at the beginning of Kong: Skull Island? With Randa going door to door with Congressmen trying to beg for any funding he could get? Presumably, then, this incident is what leaves the organization in such dire straights. And Kong is what puts them back on the map.
Yeah, and the show helps explain a plot hole I wondered about in K:SI: if Monarch and the US military cooperated in attacking Godzilla in ’54, why is the government in '73 dismissing the existence of Titans? If Monarch was discredited and the whole business classified, that resolves the discrepancy, more or less.