That is my fear, though the more panels LG makes, the lower their costs are. Apple was second to the 5K display market (with the iMac 5K) after Dell, but thanks to the volume Apple was buying, the base iMac 5K was about the same price as Dell's display.
That being said, the Dell 8K monitor is $3999 so even if Apple matched that with an ASi "iMac Pro", that is a big jump from the current $1999/2499 Intel iMacs, though it would be cheaper than the current Intel iMac Pro. This is also why I am skeptical Apple will use the 32" XDR display for an ASi "iMac Pro" because even if you de-content it to reduce cost, the underlying panel itself has to be very expensive due to it probably being produced in low volumes as it appears unique to the XDR.