Low-end GPUs often only have eight PCIe lanes to begin with, sometimes because they're using chips that were designed more for laptop use than for desktop cards. Intel Arc A380 and B580, AMD 7600XT, NVIDIA 4060Ti and 5060Ti are all eight-lane cards.
I do really think we're due for an expansion refactor. 75 Watts is an awkward amount of power and PCBs are worse than wires for data throughout and signal integrity. It feels like GPUs would be much happier if we just had a cable to plug into the motherboard that transferred data and no power and which didn't force the GPU to hang off the side of the motherboard and break during shipping
