It's not so much that the prophets of disruption within an incumbent are ignored.

It's more that as the incumbent in the face of disruption, even once you recognize the threat, it's not obvious what to do about it.

There are often no good moves–any given disruptive play is unlikely to work, especially because it's a threat to your main businesses and will go against the grain.

Since there are no good moves, the org does nothing.

The org is frozen in place, staring down the steamroller, hoping it will stop before it reaches them.

This is why disruption is an asymmetric threat.