Yes I agree with you but not everyone would for various reasons including lack of will to bother. Also although fares are displayed as one way try booking them one way and they often come out higher, as I have proven today when booking BFS-STN, it landed up despite FR's low one way fares because of timings they weren't suitable and it landed up £5 each cheaper with EZY, and this might well affect them with MAN, additionally EZY allow you to combine say LPL and MAN as a return and this often makes it cheaper, many times I've used LTN/STN and I know people who use EDI/GLA for instance. FR will no doubt always have the upper hand with pricing I'm sure.