Bitcoin has two things going for it:
The inflation is fair, in the sense that it is well known. It is also fair in the sense that nobody decides who gets the newly minted coins, everyone has an equal chance.
There is no creator still around. Nobody can dictate any changes to the rules. Sure, development is still ongoing, but if a change does not have close to unanimous consensus it's not going in. There seems to be a general understanding that unless this is so the community would be splintered which not make for a working economy and everyone would lose. Game theory holds this system in place.
(There have been a few coins which mostly shares Bitcoin's history, but so far the market seems to treat them as separate projects in their own right and valued separately, which so far seems to validate that theory.)
Not many other projects have managed to replicate the above (although some come close), so talking in terms of first mover advantage is selling the project a bit short.