Good enough for 99% of civilian cars, maybe, but I'm a lot more skeptical about the ability of battery-electric power to replace trains, long-haul trucks, etc. The expectation as far as range for those is high enough that enough batteries would either add too much weight or just flat-out not fit.

I expect long-term we'll probably settle on something like 75% batteries / 25% hydrogen for ground transportation, and the reverse of that ratio for aircraft (although I wouldn't expect hydrogen planes to be using fuel cells).

Trains? I hope that one day we see electric trains...

I'm not sure what you mean. There have been electric trains for nearly 100 years. I mean, ever heard of the TGV?

I've taken an electric train to work every day for the past year and a half...

Most of the new light rail and subway lines in the US are electric trains.

Trains don't really need it as you can just string up some overhead cables. Long haul freight should be on the railway anyway.

Electrification is great, but it's also been declining for decades in the US, to less than one percent of route miles.

Taking a figure of half a million dollars per mile (which is less than the numbers I could find, but let's be conservative) you're looking at ~130 billion dollars. That's theoretically affordable for the government, maybe, but never going to happen politically speaking.

Hydrogen is not viable. Production is inefficient, energy density is low, and handling is difficult. For long-range transportation where batteries are insufficient the real alternative will be carbon neutral synthetic liquid fuel.

Well as for trains you can still run them using wires, almost the entire European railway network is electrified

Boats, seaships, airplanes, rockets... Big-F'in'-Rockets!