Actually it does make financial sense. Here's why. Bike theft in many places now has an enormous reward/risk ratio not because the reward is large but because the risk is so minuscule -- small enough to be considered zero. People tend to think that the police would have to solve and prosecute a large fraction of bike thefts to deter the crime effectively, but that's probably not true. Any chance at all of being caught would cut the reward/risk ratio by two or three orders of magnitude, at least. Because the reward for the crime is relatively small, compared to other things a professional thief could be doing, that is likely to serve as a sufficient deterrent in many cases.

I've read that this has been tried somewhere and seems to work, though I don't recall the details. A municipality just needs to dedicate a small fraction of its resources to solving as many bike thefts as possible. Even if that's a small fraction of the total, it can be enough to turn the tide.