It might be because of plants? Planted tanks are way more popular, and plants are constantly pulling things out of the water. Maybe that - along with water changes - can minimize the issue? Probably best to add an ato (or a lid), but it evidently isn't an issue.
edit: I think there might be an influence from the competitive aquascaping world. Scapers will set up their perfect rimless tanks, run them for a few months, get that perfect picture, and take the tank down. maybe we try to emulate that, but don't consider the different timelines. But, there are also many successful, long-term, lidless aquariums, so maybe not