Meh oil companies will work it out when it's viable for them.
I bet it's no more difficult than making an oil platform, taking it 50km off the coast, sucking oil deep off the ocean floor, getting a huge oil tanker to take it back to a refinery for processing, then trucks or more tankers to transport it. They could just build their own small nuclear reactors for endless amounts of electricity to perform the procedures to extract hydrogen and bottle it.
If they can produce it, distribute it and sell it when it's more cost effective than oil they will do it.
Do you really think they will sit back and watch less sales of oil take place while consumers plug in their battery cars to the electrical grid. Somehow I doubt that. They would rather them buy hydrogen!
Hydrogen is the only model that compares to diesel or petrol, giving constant output when being used (no performance or power drop like in battery cars as the battery goes lower and lower) and it would take a few minutes to fill up the gas tank, just like what people are used to today.
The plug in and charge method is only going to suit a tiny tiny fraction of vehicle users out there, especially when rapid charge times are still at least 30 minutes and gives limited range.