You heard it here first, gang. I'm an industry insider. Okay......I'm just an idiot with a computer. Why split hairs?
So I think even the 24 inch iMac's days (or years) are numbered. They will introduce a 24 inch Studio Display (which may go by some other name) and tell everyday consumers to just buy that and a Mac Mini. The "pros" can buy the larger Studio Display and the Mac Studio. Everyone is happy!
Why do this?
1. The all-in-one has outlived its usefulness. In the age of bulky desktop towers, it offered a real advantage in space saving and simplicity. But now that the technology has evolved so that they can built powerful desktops in sleek, compact designs, do you really need them anymore?
Pragmatically Apple offers no security slots. For shared spaces iMacs are a way of locking in the complete system.
Second, Apple has self inflicted wounds here. Making the 24" as thin as an iPad paints Apple into a corner they don't necessarily need to be in for an AIO.
2. They want to get into gaming. We all know gamers have never gravitated towards Macs.
Errr. No. Not going to get many hard core multiple thousand budget gamers with soldered on GPUs.
Are people going to play more games than in the past? Yes. Is Apple counting on just that to drive unit sales growth? No. [ decent number of folks will be playing iOS/iPad games as much as anything Mac specific. That is more higher utility out of games already bought than "new growth". ]
For the gamers who are OK with a soldered on GPU the gaming consoles are a better price point. ( And not lacking for game content at all. )
While may see a 120Hz screen eventually on an Apple monitor and/or iMac probably won't see 144, 175 , 200 Hz ... or whatever the game spec wars 'demand' of a higher end monitor.
Apple may see some folks who were buying two systems ( a Mac and a PC just to game on) poor more money into just one "bigger specs than they need" Mac. However, that is not likely to be a huge unit volume driver. ( those folks were buying Macs already. )
3. Oh yeah..........if you pay for an expensive monitor and an expensive computer, you will almost definitely pay more than you paid for the iMac. And since said standalone desktops and monitors don't even come with a keyboard and mouse/trackpad, you will be paying more still.
Mini-LED panels in the 24-30 being expensive isn't going to last forever. That bigger impediment for the large screen iMac was likely that Apple couldn't convince a vendor to sell it to them cheap enough for the iMac 27 to hold its price range.
Apple's Studio display is a path to higher margins; not lower overall customer costs (via Apple only equipment).
The problem for Apple at the moment is that the monitor panel market is going in two different directions. The mainstream specs are getting way cheaper. The higher end refresh specs are past what Apple wants to do (Apple isn't chasing 'gamer specific' screens. ) .
As long as Apple picks "odd ball" resolution and panels that almost nobody is using then the large screen iMac is a bit "stuck". At least if they want to do anywhere near the same unit volume the old 27" system did.
A decent chance another contributing reason is the rumblings on "right to repair" running into Apple's "thin as possible for no good reason" iMac design rules. But even the Studio Display has "Apple only doo-bob widget" to take off the power cord. [ That system smells like someone's M1 iMac 24"/27" prototype that someone repurposed as a display. ] Apple's industrial design and that fraction are way off in separate directions. I think whatever team that designs iMac probably does need to be put in a "time out" for a year or so to withdraw from whatever they have been smoking/inhaling.
If the Studio Display doesn't end up doing as well as planned and Apple doesn't want to do something that is more affordable... iMacs will probably be back later when advanced panel pricing is more under control. ( either miniLED or OLED dual layer... whichever Apple can wrestle lower prices on. )
The iMac is the new headphone jack. Which we know stood in the way of the massive new product category known as AirPods.
Dubious analogy since Apple has removed the head phone jack never from Desktop Macs.
Where it made sense... sure it was a removal candidate. Was it completely blind dogma to follow? No.
Kill off the 27" isn't going to drive the Studio Display to take over the mid-range Mac market. Most buyers on a budget are just going to buy a non-Apple monitor. At least get more mobility and less wires with an AirPods. The Studio Display is niche overkill for the general monitor market. There is no where near the "seamless ness" in using the two together Mac Mini/Studio and Studio display versus a iPhone/AirPod. A TB/USB-C cable is a TB/USB-C cable to huge variety of another monitors also.
Note also that apple didn't start off the AirPods in some AirPod Maximus pricing point either.
The iMac 24" probably won't disappear if Apple can keep the component costs to a range they like. The 27" version could return (either as farther upscale Pro to take a more expensive panel or a system with lower volume expectations. )
The iMac won't 'rule' the Mac desktop line up going forward as the large unit volume leader by a large margin. But disappear completely? Probably not. Apple is not going to kneecap the Mini and Studio though. There will be more fratricide sales .
P.S. getting rid of the headphone jack was in part driven by the desire to put stronger haptics inside of a phone. It is a design trade off on self imposed limited volume. (as thinned out the iPads they lost it also). AirPods wasn't the sole reason. If AirPods had not taken off as well as they did... it still probably would be gone just on the haptics trade off.