The first thing you notice in a serious collection isn't the trophy plant. It's the bench in the back corner — usually a fluorescent-lit shelf in a converted bedroom or basement — where a half-dozen unflashy seedlings are growing under domes. A Philodendron lynamii no bigger than a thumbnail. A wild-collected Anthurium dressleri throwing its second juvenile leaf. A Monstera sp. from a specific drainage in Chocó that hasn't been described yet. None of them photograph well. None of them are worth showing off. They are, almost without exception, the reason the collector got out of bed at 4 a.m. to mist before work.
An expensive collection looks different. It looks like the front page of an auction site: mature A. warocqueanum in matching nursery pots, a wall of variegated Monstera, a Philodendron spiritus-sancti centered like a chandelier. There is nothing wrong with any of those plants. The question is whether they're in conversation with each other, or just lined up like cars at a dealership.