Nards, completely agree with what you say, I have a similar sort of spreadsheet, designed for the business. Certainly, the cost of keeping an aircraft, ('A' class aircraft, not PfA), doing any less that 150 hours per year is high and there is certainly no profit, (if you are operating for profitable means). Either way, you would effectively be running it at a loss, whether used exclusively for yourself, or via a business.
I also agree with Shortstripper, PfA types of aircraft are a lot cheaper to run and maintain, (and often to purchase), but only appeal to certain people. However, there is still the cost of hangarage, for those who don't have their own facilities, and for those machines that cannot be disassembled and towed away after flight, plus insurance.
CofA aircraft, especially those on public transport as opposed to private, will always be more expensive to run, but are the type that most flying schools, apart from the microlight faction, have to operate at present.
It does seem that either joining, or forming a group/syndicate, is the most effective way of cheaper (and better availability), flying as things stand at the moment.
Hopefully we will soon have the choice, what with the proposed LAPL, etc..