Why? How would a couple of extra cable prevent you from editing 6K/8K video?
I understand being less desirable solution.
The allure of an AIO is simplicity, turn it on, get to work. I wish to think no further regarding my desktop computer than I do to watch some television or listen to the radio...they're all just appliances.
The gaping hole in Apple's XDR lineup is obvious, there are XDR iPhones, XDR iPads, XDR MBPs, and, yes, XDR component desktop computers with the Mac Pro, Studio and Mini and the Pro Display XDR...so, whither goes the XDR iMac?
To me, it's a win-win world where Apple provides the tools of choice to their user base...should one wish nothing more than an M4 Max 32" 6K (or 42" 8K) XDR iMac with some TB4/TB5 ports, they can buy one, and should another user wish a more configurable M4 Max Studio with more I/O and the option for any display of their desires, they can go that purchase route, as well.
For this user, I have absolutely no need or desire to have to accommodate desk space for an unwanted bloc of aluminum along with the extra cabling/wiring and the accommodations for an extra power outlet just to do what an identically-specced AIO will accomplish with a single power cord. XDR iMac, please.
As I see it, the XDR iMac is an inevitable device. HDR content creation suffers from many obstacles as I type this, the primary hurdle, as I see it, is a full-resolution HDR desktop environment for the masses to create that content...in broad terms, adoption of new standards occurs when a critical mass of users have migrated to that technology. On this point it should be noted that Apple revealed with their XDR MBPs that transporting their "DCI-P3 1600-nits" video signal internally to their MBP XDR display is the elegant solution (eliminating a whole daisy-chain of I/O gadgetry to get a proper HDR signal to an external non-Apple display). An elegant solution that will arrive (hopefully sooner than later) with the XDR iMac.
Anyhoo, those are my needs and requests from Cupertino.
P.S. To your "
How would a couple of extra cable prevent you from editing 6K/8K video?" question specifically...if it were only "so simple" as a couple of extra cables, here's the reality in all its gory details...
LG OLED C Series (C1/C2) DaVinci Resolve Mastering Display Tutorial - YouTube
(Note: I have zero affiliation with the link's author, provided for educational purposes, only.)
...32"/6K and 42"/8K XDR iMacs, please! LOL