This seems a trivially solvable problem.

Put cheap trackers on bikes in theft ridden areas, and go get the folks stealing them.

Apple trackers cost $30 **RETAIL**. I bet one could get them in bulk for under $10.

once thieves knew they are likely to get caught, they would stop.

1000 bikes with the tracker in the padding under the seat.

1000 bikes with the tracker in the reflector on the back

1000 bikes with it embedded into the petal.

...

"delousing" the bike would be impossible in practice.

seems we don't really care to solve the problem.