If BTC will fail, it will be very hard for people to trust again on alts.
On the contrary, the death of BTC would free the alt market.
I don't think the altcoin market would be able to thrive without the help of bitcoin.
The fact that bitcoin has been so successful in such a short period is the reason why there is such a demand for the shitty altcoins
If Bitcoin dies the altmarket is DEAD. Bitcoin = crypto. Bitcoin dead = the dead of crypto. Simple ass that.