Sort of contradiction here.
Let's say you drive a £500 worth car, depreciation is no longer an issue. Monthly TCO is roughly £100 per month including everything.
After scrappage scheme, you'll likely have to pay more than £120 per month for a car, road tax has not gone down a lot at £140, fuel cost has gone down slightly but offset by having to use dealer servicing. In the end, monthly TCO is going to be over £200, more than double the previous costs.
If I were in that situations, I'd definitely not use the scappage scheme, because only offering on new cars is completely useless to me as someone who needed the assistance.
I can't see how you can argue for scrappage scheme but write off EV completely on the same affordability basis. The argument that manufacturer need the funding doesn't make sense either, how come Nissan/Renault, Hyundai/Kia, BMW, VW, JLR and GM all have EV to buy right now? Whereas Ford only have one horrible hybrid and needs the money from scrappage scheme?