Depreciation and second-hand markets for bicycles
Interesting observation. Perhaps a part of the answer lies in Akerlof's lemons' problem? 

Admittedly judging the quality of a 2nd hand bike is easier than that of a car, but from what you're describing in the US there doesn't seem to be a well functioning market for 2nd hand bikes in the US. Moreover, bikes are becoming more and more like cars in that respect with all the gadgets and technology that one cannot fix in their own shed or backyard. 

Perhaps it also plays a role that US citizens are not used to bikes and therefore have a harder time judging their quality (just guessing here, and perhaps stereotyping too much). Here in the Netherlands we seem to have a well-functioning market for them that serve all segments (including, I might add, a high theft rate), but everyone rides a bike here, so we should be better at judging their quality.