Yes, some potential altcoins has been proven could rise significantly while most altcoins stuck at some point without any chance to recover after dumped.
Shitcoins are the object for traders to pump and dump it, a fastest way to gain profits or get loss. That's why, you should choose which coins to invest properly based on some factors such as the idea, usability, developers and marketing management. Even though some famous coins such as monero, ethereum or dash seems quite expensive, but it offers a good investment as long as you buy it in the dip.