How shall I take that statement down...let me count the ways.  

Well for one you're probably building a strawman.  LeFBI might mean that there is no implied component in any contract.  However I doubt that's true.  What is more likely true he is that he disagrees that your particular implied component is implied in every contract.  In other words that your definition of "fair" is generally accepted.  

Which is your problem Joel my man is that you keep loading the term "fair" with all of your petty cultural biases.  Sure the "Implied Covenant of Good Faith" might be considered reasonable in most cultures - however it's purpose is to protect a very specific thing.  The things your contract promises you.  That is, to a point someone should not be able to use the terms of a contract to undermine the things the contract promises.  Which is rational.  It is not unreasonable to assume that the purpose of the contract is to obtain for each party the things spelled out in the contract.  However when you give an example of mining - the exchange of money for ore - clearly leaving a company is allowed as long as that is within the terms of the contract (i.e. conforms to the contracts requirement for notice) so what I decide to leave the company for does not directly undermine the ore that you got from me. Ergo the "implied covenant of good faith" has absolutely nothing to say on the matter.

Now clearly you could word a contract in a way that would deliberately restrict mine hopping or even attach some meaning to the bonus structure.  For example if you called that bonus explicitly a "retention bonus" which is for some reason paid a priori then you would have an argument.  However your long, petty, meandering diatribe about being with the company in good times and bad.   Is completely unreasonable because, broadly interpreted it significantly interferes with a persons ability to pursue a paying job ("Sorry, you can't leave until the economy bounces back!").

So as is often your problem you are equivocating. Even if every agreement included the "implied covenant of good faith" that does not necessitate your ideas about "fairness" ie. "no mine hopping".  

So until you come up with an argument to support that - your point is dead.

(And incidentally it's worth noting that ICFG is considered poor practice by the US and Canada.   From my understanding it's been replaced by "gap filling".  The...almost platonic (in the classical sense)...notion that there exists some "true agreement" and attempting to determine what that is and enforcing that rather than a specific set of cultural biases.  )