If we someday convert our deserts into massive solar energy farms, it may not even matter much that the oil technology is less efficient. There would be so much excess energy during daytime, the greater efficiency of EV wouldn't be a big advantage.
And gas engine technology itself isn't standing still. The traditional ICE engine efficiency of 25% is pathetic compared to the EV 80%. But the Prius combines both technologies and gets 40% thermal efficiency which is a big improvement. It's possible this could be increased further with more improvements in hybrid technology.
Many think that hybrids and plug-in hybrids are a bridge technology to a pure EV future. But the future may end up being a lot more similar to the present than expected. Maybe the typical car purchase in the future will be a 100 mpg hybrid with 60 mile plug-in battery range as an option. Those who have personal garages would buy the option, those who don't would not. And it would be all powered by massive solar power farms in the Mojave desert and wind farms in the mid-west. And the output from all this would be electricity and carbon neutral oil.