I don't think people with greater resources should be given more assistance. That does seem insane to me. We should provided rent/mortgage/credit relief to those in need. We should not increase payments to meet lifestyle requirements.
Those greater resources are mostly imaginary and are temporarily worthless but someone somewhere still needs to collect the debt. No one should have to file for bankruptcy and we're just discussing different methods of achieving that goal. The higher income earners are still getting more assistance either way. Which is the better method for fairness and long term economic health? I don't know. I just don't think it's insane to give out aid based on lost income. Maybe the cap should be a bit lower but I don't think it's by any means an unreasonable approach. Not for a short term stimulus anyway.
If it can allow the majority population to go through a (let's say) one month total lockdown and allow them to come out the other end not too much worse off, then it's done it's job. If it goes on long term (6+ months) then I agree, it's a farce. The long term unemployeed should all be on even grounds regardless of their prior lifestyle.
This would exclude the long term unemployed, disabled, or people fired just before the crises. Or even sole traders, self-employed. There's a reason Boris went with this plan. Its more trickle down nonsense.
I'm not sure about Boris's implementation but shouldn't the long term unemployed and disabled be covered by the existing wealthfare system. They shouldn't be seeing any difference from what they were getting before, if such a system were implemented properly.
As for those made redundant before the crisis, sole-traders and the self-employed, ideally the income test should be designed broadly enough to cover them too.
Whether or not ScoMo goes with something like that, I don't know, but that's about execution of the details. I don't think the high level concept is fundamentally broken.