I've always considered the false safety issues with hydrogen and the fact you can instead use, safer but expensive helium have held it back.
No facts of figures to support my reasoning though.
Something lay people (And children in many states) handle all the time and sit on top a huge tank of every time they go driving.
Just saying hydrogen dangers are way over rated and it's hurt progress, and part of that is because there is a safer replacement, even though it's very expensive.
There are good reasons we don't use hydrogen anymore in airships and use helium instead. There are other good reasons not to use helium, but those reasons don't trump the dangers of hydrogen, unless you knew of specific development which would mitigate the dangers that pressurized hydrogen gas presents, which I'm guessing you do not.