It's mostly because of the price. It's more on the reason on why the specific coin/token dropped in price. Developers abandoned it? Then chances are it might indeed die of no other developers take over and if there are no running nodes left. Also, with bitcoin? It won't be dead even at $1. It was made to work and to be up running regardless of price. When bitcoin was new, it was almost worth nothing. But yet, it was "alive" and working.