i would be Move onto another coin
Yeah it's a pretty precise decisions. but from that I know or think, it all will be the same thing or it could be said that altcoin has a very great relationship in the bitcoin. So if bitcoin died then altcoin will also join died, because altcoin have intake or something to be done in the bitcoin. Except for altcoin which already stands alone and does not involve the bitcoin in some ways especially on their selling points
Its really a common decision that people will surely do because its part of our nature to seek for another thing that we see that it will benefit us. When bitcoin dies then theres another crypto will replace it and people will surely transfer into it and the cycle still goes on but on the current state of bitcoin i dont think it would easily die but if it dies tommorow many will surely hard to moved on regarding on their money that they lost on investing on bitcoin.