Unless I'm missing something, the person with the fastest hashing processor will usually win. Thus there is never any reason to use an average processor, and everyone is not on the same playing field.
You have to factor in power usage as well. Unlocking a 0.1 BTC bounty while spending 0.2 BTC on electricity isn't wise.
I mean, we can easily get to the point where unlocking a secret can cost hundreds of thousands of dollars in electricity. At that point, it's not about who's fastest, but who can unlock the secret without spending too much money.