As a person who has worked with appraisers on collectibles, I can say with confidence that those purchasing NFTs in a plan to re-sell later on for huge profits are kidding themselves.
Even with tangibles, we'd have to tell people every day their stuff they purchased as a collectible 40 years ago is worth not even pennies today (because they were over-bought).
Generally, collectibles that re-sell are items that no body was planning to collect, and have become super-rare since then.
And lets face it, most NFTs are ugly looking trash these days.