soon enough people will find the best ways to optimize their earnings
Completely true. Not all people will adapt at the same speed though. But it doesn't change the fact that it cannot be perfectly balanced.
The concept of 'perfect imbalance' is to change the game often enough, in a way that regularly changes the optimal strategy, so that these fastest adapting player would be the ones winning overall. This is what you can already see happening in competitive esports game. They have the same issue that their games become stale very quick (because of high competition and very complex rules impossible to balance) and they all need to use the 'perfect imbalance' concept to keep their userbase interested.
In practise they just edit the config file (which contains all stats about characters / items) once every two weeks, based on the data of played games under current rules, and switch it up so that the game feels fresh and competitive again every two weeks.
As I've mentioned in a different comment, eSports games work because exploits are fixed, excessive abusers are banned, and countermeasures are implemented; the key being all of the above is done in a very timely manner. Steem will need a new paradigm needs to be implemented if it wants to achieve what eSports and pay-to-win games have. It's pointless if each change takes 6 months to implement.