If you have 100,000 BTC and it goes down to 0, you still have 100,000 btc.
(Keep in mind that BTC at a low enough valuation is either unmineable and thus can’t be transacted or is mineable for very little money and thus subject to 51% attacks by anyone who is inspired to do so.)
If you have 100,000 cryptocurrency tokens worth 0, that presumably means there is no activity (no transactions, no validations, no mining).
I suppose one could set up a few validators and attempt to restart the chain.
The problem is that for many worthless coins that no one wants to mine, the difficulty is too high to restart.
So that leaves forking the chain with lower difficulty requirements, which is just as pointless.
So the chain itself could become a fascinating artifact, but the magic that made it possible to move Bitcoin around would be gone.
That's such a beautiful example why Bitcoin is garbage.
If you have 100.000k shells and have 0 value you still have physically 100.000k shells you can still do things with.
While you have literally a private key representing 100.000k bitcoins with no value.