Oh yes, brother— whenever I see one of those internet posts about "prices going down," I just smash the old panic button, as the fear of losing imaginary money I have no intention of realizing completely overrides my love of collecting beautiful baseball cards
Joshing aside, do any of us collectors care about what the day-to-day, completely hypothetical valuation is of cards currently held in our collections— which are not being presently sold? It is just so utterly moot— no practical significance whatsoever.
It's not like we are cruising happily through life, see some random card or cards sell for whatever price, and then suddenly decide based on that to part ways with cards we have scoured the earth for and so carefully selected. So I fail to see the utility in making pricing generalizations— especially since the generalizations themselves are specious, because a unique card could come along and set a record. And that in itself would of course not signify an upward trend.
Bottom line, I think we collectors collect until we die or are forced by vicissitudes of fortune to sell. And if I'm facing skid row at some point years from now and have to part with my cards, I certainly am not going to shake my fists at the sky because I didn't sell at some prior "high" point, years before, when I was happily cruising along collecting.
In general, I'd hazard the opinion that if collectors online spent more time simply showing cards and explaining why they love them, instead of either prognosticating financial Armageddon or acting as if certain cards are in a competition with each other, it would be great. When I first got back into the hobby after college, all I knew was Post War classics. Thanks to enthusiastic collectors, I came to learn about so many more cards— from PreWar to Modern— that I now happily collect. All the collector-generated written content that contributed to that education was purely positive and so useful.