Here is BZ from 2007:
Probably 95% of my collection was purchased from original owners. The 'pedigrees' in my collection are not known by fandom, they're only known by me. When I look at most of my comics, I can spot the Kolmorgan, Foote, Starr, Clarke, and Gilchrist issues immediately. It makes the collecting a little more special.
Having said all of that, I do understand why there is so much ruckus about prices and potential appreciation. Collectors today spend so much money on their hobby, they'd be foolish not to give some thought to possible downsides in their investments.
Almost all my buys were 30-40 years ago. I think the most I ever paid for a single issue was $55 for Superman #1. It was purchased from a dealer who advertised it in the old fanzine, The Rocket's Blast. The market must have been slow back then because he gave me (13 years at the time) 30 days to raise the money.
Things have sure changed.