> If it was viable it would have happened already.

It is happening, all over the world, with a persistent and rapid growth curve.

> We have terrible storage and transmission, the parts that are actually expensive.

Better cut those tariffs on cheap Chinese batteries (and aluminium for the transmission).

Not that anyone would build one in the current political reality, but China produces enough aluminium that it would be viable to make a genuinely planet-spanning 1Ω power grid connecting your midwinter nights to someone else's midsummer days.