Not sure that there are enough iMac buyers who would want to pay for a 2nd stand alone display to justify the development cost.
They are coupled by component costs not the end product.
Every iMac buyer purchases a panel with the iMac. If the objective is primarily to sell single panel , the iMac buyer has already bought one of that size. So 1M/quarter iMac buyers will lower the cost of the panel component costs far more than 0.1M/quarter "affordable display" customers will. The path to a "more affordable" product will be lower costs for Apple to make the display. Using a panel that doesn't have the order of magnitude higher buying power that the iMac has probably won't lead to lower costs. Even more so if Apple uses a non-mainstream panel/ligthing combination (e.g., 5K 27" panel. 21.5" panel. ).
Without the iMac 5K volume , the independent monitor of that size will quite likely disappear.
The only way Apple gets to a more affordable and doesn't use the iMac buying power to lower component costs is if they pick a high volume , mainstream panel with very little market differentiation. That just isn't a likely path for them.
The most logical time for it to appear would be with the rumored mini Mac Pro, that is probably a bit over a year out. Another target could be an M1 series mini.
That is not particularly logical at all. The vast majority of Mac sold are laptops. This affordable panel is going to able to power every single M-series laptop that Apple sells. Also a good fraction of the Intel laptops deployed out there. Even the XDR can do that. The lower cost version is even more likely to have the feature.
Apple doesn't sell pure monitors anymore. The last top they introduced a monitor that couldn't power a laptop was 2004. That is almost two decades ago. Apple has left that market. What Apple sells is Thunderbolt Display Docking stations. They have one and only one input. No physical buttons or controls. Only really works seamless well with a Mac.
For the Mac Pro and Mini markets a substantially large number of the users already have a monitor. The start of this thread is about an ancient 30" ( a product discontinued in 2010 over a decade ago ; if not older ) that is still in active use. Another large chunk are buying 3rd party monitors. Apple's version of an "affordable" monitor is likely in $800-1100 range if it is a "large screen". They aren't going to be the value priced leader product in the overall monitor market (there will be an "Apple Tax" on them).
Apple sells about 70+ % laptops. If only 3% of those buy a display docking station then that is about 2.1% of the Mac market. The Mac Pro is likely in the 1-2% (or less) range. Taking the higher 2% and a high 50% attachment rate to new Mac Pro sales would be 1%. The laptop buyers would be twice as many.
A M1X Mini will probably have a higher Mac market share, but still very low double digits , sales rate. However, the attachment rate is going to be problematical the higher the percentage the price of the monitor is to the price of the "M1X" Mini bought. If someone pays $1,600-1,800 for a Mini more likely to take a $600 monitor than a $999 one with those kind of budget limitations (and even more likley to just reuse what they already have ) . If Min sales were 12% of Mac sales and had a 20% attachment rate that is about 2.4% . Rounded that is about the same as the laptops above.
People who pay a price premium to decouple the monitor from their system typically don't want their panel purchases highly coupled to their base system purchases. If they wanted tightly coupled panel and core system purchases then could buy an iMac. The introductions of headless Mac are the buyers more skewed to wanting higher monitor options/diversity; not just one model to choose. ( pragmatically since the XDR is priced so that only relatively few can afford it. )
There are far more Apple customers who have the "I have too small a screen when sitting at a desktop loction" problem than ones than have a "headless system with no possible monitor to attached to it" problem. If the increase of "hot desking" and hybrid work models continue for a long time the laptop group is only getting bigger.
