It is true, research is just an initial step for you to gauge if a project has a potential or not. Once the project gathered enough funds for project developent, it all depends on the whole team how will they maximize the fund and how will develop the platform/product as well as marketing which will determine the growth in the long-run.
Doing a research is a good thing. Long term investments must be done especially for altcoins I agree with that, it does not only last for 5 years, but for almost about every 5 years recorded in the history of the new economy. A long-term investor does not worry about tradings fees because they do not trade every day. Here are some altcoins in which you may invest for long term investment.
ælf (ELF)
MXC (MXC)
Zilliqa (ZIL)
VeChain (VET)
Chainlink (LINK)
Ethereum (ETH)
Binance Coin (BNB)
Tomochain (TOMO)