In suppose it's not a question of money, but the lack people willing to take such a position. It's not a glamorous job and most have better things to do with their time.

CCTVs for a long bridge/tunnel might be enough. As it would take quite a while to leave they do not seem like an ideal mugging place?

Drunk people, homeless shelters. It's a choatic area in Amsterdam, will attract lots of things and certain people don't care about CCTV, hoodie is enough to cover up. Police is always understaffed in nights of a weekend so they just don't really look forward to a new hotspot they need to go and check up on. Just happened last week that a friend jumped in between a 16 year old boy being beaten up, the police eventually came but left quickly and didn't want to call an ambulance because of lack of resources, he had to go to the ER himself. Turns out it was so bad he needed surgery the next day.

Would you take that job for 50k/year? I wouldn't. Would you take it for 500k/year? I would. So, it is a question of money at the end of the day.

Not in any realistic scenario, no.

The ferry needs at least 2 people on it, right?