A1 - the point you are missing is that previously that 5-bed home was available for rent at an afrodable amount. However, by popular acclaim the house was privatised and has now ended up owned by a private landlord. The 2kpcm charged is against the 0.5kpcm that the same property used to cost. It is this reason and this reason alone why the family in your example require housing benefit to meet their rent. Tenants are not the ones exploiting the benefit system, but are being exploited as a means for landlords to maximise incomes - as was the stated aim of government when they deregulated the rents.
Briefly - on earnings of £35kpa a mortgage of £150k may have been ok under the deregulated banking debacle, but relistically to be sustainable a £40k deposit would now be required.
Now, in the real world benefits postion. Your 'dad' happily trips out and takes that minimum wage job which you say easily bridges the housing benefit gap. What you are ignoring is that the benefit tapers across the benefits paid combine to reduce the overall income from wages towards zero or even to a negative. That is why 'IDS' proposals to unify benefits has merit (so long as it avoids the minutia repetative means testing which will cost more than is saves).
Security of tenure, reasonable living standards supported social welfare, and social inclusive fairness are all positive aims for a civilised society. When the share of the nation's wealth production is fairly paid in wages the demands on the welfare state and hence its costs are lower. Over the past 30-years the polarisation of profit into the hands of the elite (recorded and reported across all commentators left and right) has meant the creation of a low wage economy, increasing benefit dependence at the same time as resricting the pool of potential tax income from the reduced earnings of the majority. Adding into this the removal of available social let housing and its replacement by high charge private housing and you get the scenario that we now face.
At no point has the tenant or the benefit claimant caused this circumstance, other than to vote in the governments legislating the disaster into existance.
It is depressing the number of site posters who seem to be, in one shape or another, demeaning of those with less than they but jealous of those with more, except where those with more are members of the elite when it appears their right to wealth is unchallengable. Why Alpha One can you decide who deserves to live where? Why Alpha One can you decide who deserves to earn what? Why Alpha One are you so jealous of those who have advantages that you do not have?