I think your bicycle/oracle distinction is interesting. It seems like the tradeoffs in preferring a bicycle to an oracle are similar to considerations leading up to decisions not to abstract. If we could assume the oracle would fulfill its function perfectly, there would be no real reason to prefer the bicycle; unfortunately, however, experience shows us that the internals of complex black boxes we construct are rarely perfect, and that opening the box may be necessary, and unpleasant. On the other hand, with a bicycle, a feeling of control remains throughout: it's always understood how some action on the bicycle will evolve the state of your situation. The downside for the bicycle is that its definition requires it to remain relatively simple.
My first thought for getting around this was something like formal verification that a black box does what it says—but once 'what it says' is too complex for a person to really understand (e.g. a black box containing the behavior of a human brain), you've hit a wall with this approach.
The other thing I can imagine is building up 'bicycles' which have parts of proven-correct medium complexity, arranged together in a single higher-level system also of proven-correct medium complexity (where medium complexity is: more complex than bike parts, but still with readily human-comprehensible semantics). I'd characterize these systems as sort of like Iron Man suits. Maybe that doesn't really add anything of practical benefit beyond the original bicycle analogy though ;)
Not only might it be more fun, but you'd build a better intuition about what to expect from it (or even how it works).
It's like how people often make fewer mistakes with slide-rules or abacuses than pocket calculators, since the former two require you to check your answer against your intuition, while the latter just tells you "the answer" to your (potentially ill-formed) query. Trusting a black box can be quite dangerous.
I threw 'real' in there to cover that. Maybe that's not fair though ;)
More seriously though: if the oracle were perfect, you should have to do almost nothing (i.e. the relative time savings would be near 100%; e.g. creating pizza: the oracle, you just tell: "get me pizza", whereas with the bike, you have to bike there—which I admit may be fun)—so as long as you have things you enjoy doing more in your non-productive free time, then it shouldn't be an issue. (Not that I think that's necessarily likely...)
My first thought for getting around this was something like formal verification that a black box does what it says—but once 'what it says' is too complex for a person to really understand (e.g. a black box containing the behavior of a human brain), you've hit a wall with this approach.
The other thing I can imagine is building up 'bicycles' which have parts of proven-correct medium complexity, arranged together in a single higher-level system also of proven-correct medium complexity (where medium complexity is: more complex than bike parts, but still with readily human-comprehensible semantics). I'd characterize these systems as sort of like Iron Man suits. Maybe that doesn't really add anything of practical benefit beyond the original bicycle analogy though ;)