> We have railways running from West -> East, why not include power lines that can take power from energy farms in the West -> East?

Firstly, there is no such thing as an infinitely scaling system.

Secondly, because power transmission isn't moving freight. The infrastructure to move electricity long distances is extremely complicated. Even moving past basic challenges like transmission line resistance and voltage drop, power grids have to be synchronized in both phase and frequency. Phase instability is a real problem for transmission within hundreds of miles, let alone thousands upon thousands.

Also that infrastructure is quite a bit more expensive to build than rail or even roads, and it's very maintenance hungry. An express built piece of power transmission that goes direct from a desert solar farm to one of the coasts is just fragile centralization. You have a long chain of high-maintenance infrastructure, a single point of failure makes the whole thing useless. So instead you go through the national grid, and end up with nothing, because all of that power is getting sucked up by everyone between you and the solar farm. It probably doesn't even make it out of the state it's being generated in.

BTW the vast majority of the cost of electricity is in the infrastructure, not its generation. Even a nuclear reactor is cheap compared to a large grid. New York city's collection of transmission lines, transformers, etc. (not even any energy generation infrastructure, just transmission) ballparks a couple hundred billion dollars. Maintenance is complex and extremely dangerous, which means the labor is $$$$. That's what you're paying for. That's why as we continue to move towards renewables price/watt will continue to go up, even though we're not paying for the expensive fuel anymore. The actual ~$60 million worth of fuel an average natural gas plant burns in a year pales in comparison to the billions a city spends making sure the electrons are happy.