The thing about comparisons with Synero and others is that the others haven't even started. So we have no idea of whether they will succeed or not.

The success of a cryptocurrency does not depend solely on it's scarcity. If that was the case numerous scarce cryptos would be more successful than the inflationary cryptos like doge and yes, steem. There is another ingredient required - popularity, accessibility. Steem has the latter going for it...