If the caps are so short and arbitrary, unless I'm missing something, the state is pocketing a ton. Perhaps that's okay, because it does definitely defend against the "everybody's out of work" scanario that we haven't really had in awhile, despite the recession. Or maybe it just means that there are more people who need it more than I'm envisioning, or that it disproportionately favors the lower incomes, or any other number of factors.
The point though, which I've perhaps done a poor job of illustrating, is that it still behooves the state to ensure that earners with high wage potential aren't made homeless as a result of those caps.
If the higher wage earners get less benefit from the system, then so be it, but that means that the system needs them more than they need it, and as a result, should probably not be bankrupting those with high income potential, just because "we shouldn't be debt servicing their assets".
That's not how "social safety nets" work. They tend towards being zero-sum in monetary terms, which means that some people will "win" (those worse off, hopefully) and some will "lose". The idea is that such devices help balance and stabilize society, which means we all actually win.