That 'semi worthless' comment is quite right and has been so for some time. I realise that a/c choice is determined - to a large extent by what you want to do with it. Most of my GA flying has been with the heavier types; irreverently referred to as 'spamcans'.
I came to my senses when presented with the invoice for hardly any work at all amounting to a whisker under ten thousand pounds for the Annual on my Robin. I sold the a/c and bought Permit. Apart from night and IFR my flying was the same. Now, apparently I have the benefit of both.
TOO, I have benefited by thousands of pounds in terms of massive savings on fuel, maintenance and servicing costs. I use LAMS as my guide and do all my own servicing. Every contingency you listed is included in my balance sheet, including car fuel to the strip where the a/c is hangared. I fly, in a Group A a/c, for £48 per hour variable according to the cost of mogas and which includes an hourly amount of £12 for servicing and the engine fund. The hourly rate can vary again according to hours flown and their effect on fixed costs
The a/c I fly, is in some respects, better than the old fashioned stuff but in others; cruise speed for example, it is not so good.
Jay Sata's comments are correct. These old types have had their day, that is why you can pick 'em up for peanuts !