Digital Combat Simulator (DCS World) has some really tiny text on the cockpit dials and screens, and distant targets are often only a few pixels in size. Those 2000+ vertical pixel HMDs I mentioned don't have any issues with cockpit details whereas my older Samsung Odyssey+ required constant use of the zoom button.

Furthermore, the performance hit when upgrading to higher resolutions is negligible. Smaller pixel densities require heavy supersampling to look good whereas higher density displays can be run at or near their native resolution.