It's just real suicide when you invest in such coins without proper knowledge of when to sell them because the timing is important in this matter and when the price dumps, you won't always get a chance to recover your capital. that's why you don't invest in this kind of coin with the money you can't afford to lose or else you will regret it big time and it will be the same reason to quit altcoin investment because of the trauma you will suffer when you don't follow that basic step when it comes to investment.
Investigation about coins is very much important if without investigation you invest large amount in unknown or scam coin then may be you never invest again in future. People do mistakes each time and when they loss money then they leave crypto space by saying that altcoins are not good for investment. If you cannot learn well that at which price you have to buy or sell then there is no need to invest huge amount because you are calling your defeat by yourself. Make and think a target and if you don't have profit then leave your investment for some longer period.
There is no doubt that some altcoins become disappears during bear market but don't forget that there are also lots of successful coins that make its holders rich. If you are putting money in unknown coins and are in hope that it will give you return then you are not trading or investing but you are gambling which is not profitable way. There are numerous old coins like Ethereum so don't leave it for new coins because Ethereum can increase your money but new coins can force you to not trust any altcoin again.