If the spike communication protocol is known, then even in 20 years you would be able to design a new node board. The actual hardware used on them is not that important, as long as they understand the network protocol to talk to it.
Lucky for us the mission pinball framework project has already partly reverse engineered the spike networking protocol. The hope is that they are able to fully decode the protoco. Even better would it be if Stern release the protocol specification.
So the wait is for the full protocol spec and someone designing a third party node board.