Look, Kikiyama's website is a thing based on something physical.
Be it that someone is paying for it, or that it's hosted via someone's personal equipment, it is something that continually requires someone's attention/dedication.
Why in the world, would Kikiyama not have made (or simply not make, since time's not short) any changes to their active website?
They can say whatever they wish, the Steam developer(s), but we have no verification..
Their reply in the screenshot you've posted is literally at the credibility level of gossip, since they've just written what they have, without ANYONE verifying it(anyone who could verify it)..
It's the same as the supposed Kikiyama here, it's based on blind trust.
The copyright is all the new game has.
Kikiyama might have died a long time ago, or something.
That's just a crazy guess, but we don't know.