Because when new bull run will arrive there will be new shitcoins and your shitcoins will end dead or delisted from exchanges which can lead to 100% loss.History is always repeating.
5,5 years old chart:
Surprisingly some coins from this chart are up from then but volume on exchanges is low,so holders of these coins are truly bagholders.
I agree with what you say and I am sure that many shitcoins can also disappear if the market fails to recover quickly; many ico improvised in 2018 that have collected little could end the funds and abandon the project.
Different speech instead for many Coins that have lost more than 90-95% of their value but who have all the potential, team, community and foundation to get up and resume the growth trend; these can be for example: Stellar, Eth, Iota, Neo, Monero, Cardano, Dash, VeChain, Qtum, Omg, Stratis, Zilliqa, Nano, and many others ..... with these coins if you know how to wait you can have enormous satisfactions in the next 3-5 years.