Blockchain, @stompix, cannot run out of full nodes or do you see a situation where it happens?
Again, neither the blockchain nor nodes are something that exists like air everywhere without human assistance, they are databases, and nodes are the copies of that database hosted by someone, if those persons decide it's not worth hosting the nodes anymore as the said shitcoin (BSV in this case) is worthless then there will be no reachable copy of the blockchain anywhere and nobody can run it anymore.
Go to the end of the altcoin announcement board here
https://bitcointalk.org/index.php?board=159.0;sort=last_postAnd check, are all those dead shitcoins's blockchains still reachable?
However, I have a question, when they are no full nodes available and later on a full node connects to the network would they be a means of retrieving transactions that happened during downtime?
If there are no full nodes there is no mempool, and there is no network at all, so if one full node comes back online from its slumber it will have no idea what happened while it was offline, it will have no idea even about the blocks that were mined after it shut down.