Yea, most of if altcoins can't survive in bear market and stop after 5-7 months. That's why we must carefully search any project with good benefit for their investor. And i think the project who always dissapointing their community is also very bad for the future of the project. Like the delay of their plan.
Altcoins are not trustable each and every time because there are thousands of altcoins but only few can accomplish well beside which every other altcoin loss its value as time goes. Altcoins can be selected by examining its advantages and use cases and also look into its market cap so it will be easy for you to choose valuable altcoins for longer duration.
There are some strong projects like Ethereum the appearance of which shows that as bitcoin is successful so some altcoins can also be successful in future. Create a plan and search about different coins then realize that which coin is accomplishing well and never died in 12 or 13 years so it will have positive influence on your decision making ability.