We get ourselves some instant noodles, gather all our plushies by the fireplace, and watch KillerBean on the family television

TLDR; Pipis can't hatch without Spamton's presence, and likely never will because it doesn't recognize him 🥀

Now why didn't it hatch when Spamton was present?
well, if Tenna doesn't recognize him, I don't think the Pipis would either

However, if we take the main Pipis to the Z-Rank room (likely Spamton's room), it will start "chirping"
This could mean that it cannot hatch without Spamton's presence

Before we can talk about our main Pipis, let's look at the others
in both SNeo's Fight and in Weird Route, they will hatch to attack (probably a command from Spmaton)

a study showed that baby crocs that started communication hatched within 10 minutes
meanwhile, the crocs that had no sound or croc signal hatched within 5 hours when testing the mothers, it showed that they started digging the nest in response to the croc signal

I remembered recently that baby crocodiles rely on communication in order to hatch, with the babies chirping to signal to the mother that they're ready
scientist theorize that crocs do this to increase survival rate (source: sciencedaily.com/releases/2008/…)