"Consider?" Why? If a feature contributes little-to-nothing to your workflow or user experience, but adds significant dollars to the purchase price, what is there to consider? The whole marketing narrative around the ASD's "super-high maximum brightness" just reminds me of the old Corningware "
withstands heat that turns ordinary saucepans into sauce" commercial.
Sure, there are people who benefit from that level of brightness in a computer monitor, just like I'm sure there are people who benefit from a saucepan that can double as a crucible. But that's not typical of most people actually buying either product.
This isn't a lack of competence on the part of manufacturers, it is simply the state of the market. As long as the 5k space is populated with mostly Mac users, there isn't going to be a lot of competition to speak of. And unfortunately for Mac users, the 5k space is probably going to be populated primarily with Mac users for the foreseeable future. The only people who really think they "need" 5k monitors at all are those who are receptive to Apple's marketing machine, as nobody else is really pushing the benefits of a 5k monitor.
The fact that the market is absolutely flooded with 4k monitors should already tell you what most people think about what is "needed" in a monitor. Heck, most computer users aren't even at 4k and they're perfectly happy. I always get a chuckle out of the weird "is it Retina?" discussions that go on here whenever someone is talking about monitors as if 1440p wasn't the pique of Apple's branded stand-alone display offering only one iteration ago. Heck, as I type this right now I'm looking at two relatively old 1440p BenQ monitors and an LG Dual-Up which, altogether, cost me less than a single ASD would have, and I have no complaints to give about text sharpness or colour accuracy with my setup whatsoever.
Whether real or just perceived, 4k to 5k seems like a rather incremental upgrade for most people. What is more likely to happen is that the rest of the market is going to forego 5k altogether and jump to the next logical upgrade, which would be 8k. There are already
some pretty reasonably priced, excellently spec'd 8k monitors on the market today, and they're likely to come down by a lot within the next, "um, FULL DECADE." And, while I'm sure Apple will probably have something like a 9.5k monitor out at the same time, and you lot will still be swearing up and down that anything less will be some kind of grainy eye-torture and will probably complain about "lack of competition in the 9.5k space", the rest of the market will continue to not really care.