> As in, it's more likely you get a dead pixel on a larger screen.

Aside from the ink capsules and higher voltage (though still very low), E ink is almost identical to LCD and probably slightly easier to make. There's a TFT (which can have a larger footprint, since it doesn't need to be transparent) on the back, an LC or E ink capsule layer, and an ITO electrode. Dead pixels are almost always caused by damage or defects in the TFT.

I wouldn't say it's artificially out of reach, though- setting a line up to produce large panels is a high opportunity cost. If anything is artificial about it, it's that you presumably can't buy E ink capsules yourself. With enough effort you might be able to separate the top glass from an LCD TV, dissolve the LC, and replace it with E ink, but I have no idea how you'd do that. No promises it wouldn't burn out the TFT immediately.