Cheap single bus tickets considered harmful

Here in the UK, the government placed a £2 cap on single bus fares. Cheaper bus fares is a good thing, surely? The snag with this limit is that, at least in Cambridge, it makes 2 single tickets cheaper than a return (OK, there isn't a return, there's a day ticket). It's even cheaper that the advance flexi ticket (which is the day ticket on the smartphone app). (One possibility is that the single…