Going back a few years, my last bike theft was dealt with very quickly and efficiently by a couple of officers who knew what they were up against. It's a shame that things are so variable but I wouldn't say they're all useless, that just leads to a "why bother" attitude which doesn't help anyone.
You also have to bear in mind that most bike thefts in Bristol are fairly small potatoes. For every one like this, I get sent 5 or ten bikes that are worth less than £500, if that. Of course these bikes are valuable in lots of other ways but so are lots of things that get stolen. It sucks, but bike theft is almost certainly a symptom of high levels of cycling rather than something that's going to curtail it. Look at Amsterdam, it has a massive bike theft problem but still has plenty of cyclists.