“The thing is there can't be more than one phone system, ever. The moment someone invents a new phone system, someone will create a gateway to the old phone system, and the phone system will live on.”
Thus far, this is true. The global phone system has persisted for almost 100 years, evolving via numerous “gateways” to older iterations of system (e.g. land lines -> cell phones, copper wires -> microwave links -> fiber optic lines, in-band signaling -> out-of-band signaling, individual lines -> multiplexing, etc.)
Yet despite the same phone system evolving and persisting for almost a century, dial-in BBSes, Minitel [0], and other outdated technologies that use phone lines are completely dead. Just because a communications medium may persist for a long time doesn't mean protocols utilizing the medium will.
The claim was not about the medium, but about the content ("a 500 year old seeded-torrent"). Phone system has never stored any data (other than the mapping between phone numbers and addresses or, lately, people), and was usually upgraded in a backwards-compatible way.
I think that's the important nuance: humans have always had a keen interest in keeping records of history. We are at an early age of electronic computers, but we've already got things like archive.org — that's likely to persist in some shape or form, just like we are actively trying to persist books and movies from different eras.
Other than natural or civilizational catastrophes, I only see the risk in the amount of data needing storage surpassing any one's entity ability to archive it, but I am sure "humans" would deal with that in due time too.
Edit: I do not necessarily believe the torrent claim, but wanted to clarify why I see a point in it.
Thus far, this is true. The global phone system has persisted for almost 100 years, evolving via numerous “gateways” to older iterations of system (e.g. land lines -> cell phones, copper wires -> microwave links -> fiber optic lines, in-band signaling -> out-of-band signaling, individual lines -> multiplexing, etc.)
Yet despite the same phone system evolving and persisting for almost a century, dial-in BBSes, Minitel [0], and other outdated technologies that use phone lines are completely dead. Just because a communications medium may persist for a long time doesn't mean protocols utilizing the medium will.
[0] https://en.wikipedia.org/wiki/Minitel