So what is the solution to bikes getting stolen? It seems like we cannot really make locks that are cheap enough to manufacture to prevent thieves from stealing bikes/harvesting them for parts. Do we put GPS trackers on all bikes? Can we enforce harsher punishment for bike thieves?
I think bait bikes are a good solution. Put out a few normal looking bikes with gps trackers in them, and have stiff fines for those who get caught. Making locks safe against an angle grinder isnt really feasible, but making someone think twice before even trying because it's a bait bike might work.
Firstly, bait bikes are inevitably going to be cheap bikes. Thieves are more interested in expensive bikes - and if the expensive bikes are not only more profitable, but also safer to steal, then they're bound to step up their lock-picking and angle-grinding game.
Secondly, finding someone to organise this would be difficult. Any single organisation sufficiently large enough to do this would be bureaucratic enough to insist on the same make/model of bike (for the obvious homogeneity benefits), which would make them as obvious as an undercover Crown Vic. Conversely, any kind of grassroots or community effort would (by design) need to alert as many people as possible to the venture, including the bike thieves themselves - thus spoiling it before it even begins.
Finally, these things are chop-shopped almost the instant they get on-sold. Tearing a bike down can be done in a public park in 5 minutes flat with a pocket's worth of tools. The bike thieves can adapt a lot more easily than the sting operators.