Well, I understand why investors behave like that, well it's clear because only these two coins are BTC and ETH that have a solid fundament, most of the altcoin today the idea is not needed publicly, or many people are traumatized by investing in new coins that are scam rated. maybe someday there will be a coin overtaking the top two coins. with a fresh idea, with strong fundamentals, with a careful and smart professional team, and most importantly the coin must understand what the market needs
Investors are afraid of the market conditions. Market conditions change everyday in a bad way. BTC does not give permission ant alt coins to go up. While BTC increasing, alt coins decreasing. While BTC decreasing, alt coins decreasing. While BTC stable alt coins decreasing. Most of the investors afraid of putting money on alt coins. If they decided to enter, they are using strict stop losses. Alt coins can not get the momentum which they need for going up.
In todays marker conditions investing on Top ranked projects are secure. And as you mentioned strong projects must be selected for investment.