Believe it or not guys everything you have mentioned above is known and has been known for sometime.... Jo public is just catching up. It is the reason wholesale funding markets has been shut for over a year and there are calls to recapitalise the banks.
Bad debts have yet to really spike or threaten bank levels of bank capital so all of the measures currently being taken are in anticipation of the events you talk about. Most losses to date at banks have been taken on debt securities where mark to market losses force banks to take future losses today. Loan losses can be spread over a greater time period and at least partially be absorbed by ongoing earnings. Total "cash" losses on sub-prime to date have only been 5-10% of the write-downs booked by the banks. I am no a bull on the economy but the banking sector and markets have moved well ahead of your thinking..... the government intervention and bank recapitalisation is a big step forward and will help stop things getting even worse.
Topslide the US & UK government intervention was necessary. Without it the FTSE would be much more than 1000pts lower. Time will tell and I have been uber bearish on this site for months but it is churlish to ignore positive and necessary steps that are being taken. And the £500bn will be collateralised so the bulk will be repaid. It is not "spent" like the money on the Olympics so your comparison is not 100% accurate. The governement will also actually make money on the capital injected into the banks given the coupon they will charge relative to their cost of borrowing. Banks will repay this 10-15 years down the line once they have rebuilt equity organically.
The people I talk to are very very positive about actions taken this week and I am comfortable many of them know what they are talking about.