Pilferage from bags is very much still a thing, and some US airports are a bit more 'rustic', in their setup, than those in Europe. A big factor in the decline of theft at LHR and other EU airports is that those reviewing the bag imaging are physically separate from those handling the bags, making the contact between one and the other rather hard (bag pilferers target specific bags they'll know will contain goods of a certain value). ICTS bag screeners are located away from all bag handlers in LHR, whereas the TSA screeners often sit in the same place as the baggage handlers. It's not unusual to have a TSA screening machine on the belt loop fed straight from the check-in area, which is a setup that I have only seen at small airports in the Greek islands but which, in America, is visible in many large terminals (including JFK).