It's because we people always go for the most popular thing and the first, whether it's a coin or a token, or even a television show. Anything!
Take for example bitcoin. There are existing cryptos or coins that are currently more scalable, fast, and better security and privacy focused than bitcoin. But still people prefer to use bitcoin than those coins not because it's better (even if it's not), but because its the first coin and also it's popular. We humans have this kind of difficulty to adapt to something new because of those things that we are already used to. Even if we say that we can adapt through time, it's still slow, and we are still not open to the reality that there will be things better than the other or there will be new unknown things to come; same as there are some civilizations that are more advanced than our civilization.
Same also with Fiat Vs Bitcoin situation. We say that we love bitcoin, we love crypto, we love decentralization, because it undermines governments and central banks, but at the end of the day we still have to convert that bitcoin or altcoin to fiat not only because we need it but also because we are used to using fiat. And this also goes to your question about tokens on Ethereum blockchain, and everything else.
Imagine if we eliminate this kind of barrier in our minds and open our consciousness to the reality and accept the reality that things will have a constant improvement and evolution NOW. we will have no governments, presidents,kings, central banks by 2020 and will be replaced by decentralized blockchain powered AI whatsoever that analyzes all data in all parts of the world for social, cultural, geopolitical, psychological, political, emotional, agricultural, technological, geographical, etc. you name it; and then will decide what to do per town, community, city, state, or even per country. And that will be the start of SKYNET! haha!
