From the article: "Mazetti estimates that in a decently trafficked location in a dense city, a Wheelys coffee shop might do $400 in revenue per day and keep about $200 after the cost of goods."
Say 8 hours/day and you're looking at $25/hour, which I guess is pretty far above minimum wage, but is someone for whom $25/hour is an upgrade in a place to spend the $3k to buy in?
And if you're operating in a slower area you're not that far from making minimum wage. If I wanted to operate a fleet of them I don't see how I come out ahead after salary, overhead (increased loss from the minimum wage employee) and taxes. Even at $175/day your looking at $21/hour income after COGS, pay someone $12/hour plus taxes and overhead and you're profiting maybe $3/hour/bike.
I guess once you get to 30 or so you're starting to make real money. But at that point you have to wonder about saturation of the good spots.