Hydrogen vs. Battery Electric Cars

Hydrogen will see more use in industrial where machines/vehicles etc will need to be ran for long periods with little down time. Public will most likely be ok with battery as most only use their car a few hours in a day so plenty of time to charge the vehicle when not being used. Its like how petrol and diesel used to be.

What I don't get is why companies are dicking about making these expensive fuel cell tech, when they could make a few adjustments to a normal engine and have them running hydrogen right now.