Sadly, to build a community around a coin, you'd still need staunch supporters right? And most, if not all, would try and use the money to advertise it so in the end, it falls to the factor of, again, the problem of money.
Besides the lack of promotion and lack of volume, DEX also the trustless system which need require deeper knowledge to control it, this is what the newcomers avoid the platform, plus the UI/UX that are not familiar in the eyes.