I sounds like John ("Old guy") got a decent deal on his Ferro mill. I think sometimes we fuss too much over the price. Buying old used machines is sort of like getting a lottery ticket (just much better odds) - perhaps it will be great and perhaps not. Also if it is near by, fits with one's own timing and various non-commercial factors - then for the individual doing the purchase it may well be worth the price but it would not be worth it for someone else. By the time John got to the end he had a good machine for a decent price. Certainly there are the stories of machines that just need a little cleaning / servicing and they are awesome. I have been fortunate to land a couple of those - "pretty well stole it" deals.
An important aspect is what it gets used for. Probably my best "deal" was my first lathe, an Enterprise 15x60 that paid $9,500 with nothing for tooling and another $600 to move it (as lathes go, it really is nothing special). That was a lot of cash in 1983. What made it a really good deal is that I have used that machine a lot over the last 37 years (still the go to machine), I'm sure I have spent more than the purchase price tooling it up. I've no regrets, the machine has been zero trouble and a learned a ton - basically it led me into a lifelong interest.
On the flip side I got a great Huron mill, "just needed a little TLC" - cheap, only $500 (which included delivery). I have since spend 200-300 hours disassembling, cleaning, making small parts - I'm still in the midst of it and it feels endless (I'm now at the point of test running and finding more small issues). Of course the time is chalked up education and entertainment. The output (making stuff, even when it isn't for profit - none of my machines make me any money) compared to what I've put into it (mostly time, some money), that Enterprise lathe was certainly the better deal.
I really enjoy hearing people's rebuild stories. I've fixed up a number of machines (never right to the last nut and bolt, and then painting), but I have never put the effort into documenting so much detail. My "hat is off" to guys like John that persevere through such a effort. By comparison I may be the type that would get about half way through and run out of interest - so it was good to see him carry it right through.