If BTC dies all crypto market dies..I dont think that another coin can replace it, i mean, i dont speak abot technology and so, of course there is already existing projects which technology is more progressive. BTC is main currency, digital gold, there are no alternatives with such big credit of trust.
If it happens (hope, not) many people will lose huge amounts of money. Bitcoin is the number one choice for most investors now. Yes, sure, later, in 20-30 years, another cryptocurrency can become a leader but not now.