One problem can't solve from first, if new investor can't trust new fresh coin why they don't invest in old coin. We several good coin already exists in cryptocurrency even with very low price. Even I don't think there could be a trust problem. All solution is now is the correction time!!
People easily find new projects more attractive comparing the old one, maybe because of the hype and marketing strategies something like that, I don't think trust is an issue here the old projects are not known to many new investors, that's why investors are just picking up from those new projects. and we cannot blame them because it was the fastest and most convenient way to invest in cryptocurrency, my suggestion those old coins must continue to do marketing strategies such us campaigns to tell the investors in these industry that we are still here and open for business.