I think a major problem is that living is just so expensive and wages are too low. AI tells me that the average rent for a 3 bed house is £1300-£1700 a month, depending on area.
Minimum wage after tax and NI is £1780 for a 37.5 hour week, so it is clear that there is going to be little of that left after paying the rent. If both parents work, they need to pay £600-£1400 month if they claim government funded hours (depending on the age of the child), so again, there will be little left over, and it is very hard work running a home and bringing up children with two parents working full-time.
If that couple see another couple with neither parents working, or one working and getting benefits and top-ups it is not unreasonable for them to be resentful. They must feel as though they are running to stand still. Surely it is wrong that two people working full time can't afford to have a decent lifestyle and bring up children, when those with one or both of them not working can?
Yet it is often the same people who say that benefits are too high who object to rises in minimum wage. Something has to give. Either rent caps, higher wages or cuts in benefits. If none of those things happen, we can look forward to more resentment of everyone by everyone else, more people deciding it's not worth 'playing the game' and trying to provide for themselves (never mind everyone else), and less money to pay for public services of any kind.