The market is wrong. But first let me concede that iGPUs are critical in smartphones and useful in laptops. I was talking about desktops.
The problem is this: Space is at a premium inside the CPU, but is many orders of magnitude more available in the rest of the case. This is even true in 'slim' form factor cases. Some dGPUs are extremely tiny and don't even need a PCIe x16 slot. The space currently taken up by iGPUs is very much more useful as part of the main processing units, and a dGPU could replace the iGPU at any price point, and in any form-factor case. I am absolutely certain that is the better way to design them. I will say that, perhaps, a very minimalistic (and much much smaller) iGPU is useful for troubleshooting. But Intel and AMD should stop wasting space trying to make iGPUs competitive for gaming, like they seem to be doing. Such is properly the role of a dGPU. Most consumers won't even notice, because they never open their cases anyway. But they'll appreciate the lower cost, and enthusiasts will appreciate the better CPU performance or lower heat. Better all around.
