Bike thefts soar by 75% as organised crime gangs move in

He said: "One reason is that there are a lot more people cycling, and another is that because it's more popular, there is more of a market for stolen bicycles. I am a keen cyclist so I do feel for people and know how infuriating it must be."

I think the key word there is MARKET

precisely.

If people stop buying stolen bike (and the worse thing is, they know it's stolen), theft find it harder to sell their stock of stolen bicycle, thus theft less likely to steal more bike when there's a smaller/no market for it.

If you arrest theft, they'll carry on if people still willing to buy stolen bike.