I like the idea of hydrogen, but I've heard it's hard to store long term because the size of a hydrogen atom is so small (literally the smallest) that it leaks through containers more readily than any other gas.

You are correct that there are infrastructure issues...Hydrogen also likes to be a gas which takes up a massive volume, and makes it hard to 'pump'. It needs to be stored as a liquid with massive cooling and/or pressurization in terms of creating the infrastructure to completely replace gasoline. I will grant that this is a substantial enough issue that it would take too long to go straight to hydrogen cars from gasoline. Electric is likely something we have to make due with for now, but I don't think it is ideal. Hydrogen adoption at the grid level is probably the best way to begin. Use the excess electricity produced by solar and wind to perform electrolysis, and use the hydrogen for off cycles