One reason makes sense, but if we talk about exchanges, it should be that when developers want to list tokens, they can choose not to register the tokens they have.
This year there are a lot of new projects running IEO, I think investors already know what they are choosing while making decisions in investing.
Or,,, go back to the good old days where developers did not care about listing and markets and simply just developed. When you continue to build and show people what you have, maybe people just decide on their own to trade it? Maybe exchanges decide on their own, hey we like this coin and we will list it, is that not how things used to work?