I apologize if I come over as pedantic, but some leakers tend to rely on people they know to leak the information to them, sources they get information from. This way the actual leaker, the source, is less likely to lose their job, as an acquaintance of them actually spreads the information around but can still spoil the surprise because some people are just a bunch of *****.
But anyway, I personally think he actually has some of these sources, but as
@TheDarkMetaKnight said,
the possibility of a Gematsu repeat should not be ignored. Leakers aren't always right, no matter how credible they are. A Castlevania bundle was recently revealed for the PS4, and not the switch, like Vergeben believed. Even the most credible of sources can mess up. At most one should consider the possibility of a leaker being correct, instead of treating it as gospel. And besides, as K. Rool and various other characters have shown, he doesn't know everything.
On a slightly different note, regarding the box theory, I'll admit that I believed the music theory to be a realistic theory, so with this week's song in mind, I genuinely believe the box theory has a decent shot of being wrong. Not guaranteed, but I don't feel like two characters, including echoes, is all we have left.