Electrolyzers are expensive and capital intensive enough that we don't anticipate that green hydrogen will compete with natural-gas derived hydrogen on cost before 2030.
By 2030 batteries will haven fallen dramatically in cost. It's not enough to show that electrolyzers are falling in cost, it also needs to be shown that they are falling faster than batteries, and will be able to catch up.
That's the missing logical link, and I haven't seen even the most optimistic hydrogen boosters produce numbers that show it to be possible. Definitely not before 2030.
There is a massive hydrogen PR push right now from natural gas companies with the hope that they can eek a few more years out before transitioning to the modern renewable economy. But even those folks don't say that fuel cell is going to be cheaper than typical passenger vehicle sized batteries.
Every single hydrogen powered vehicle is already going to have a battery in it, to manage variable output. The question is, if hydrogen machinery gets cheaper than battery, at what range capacity does it make sense to include both battery and hydrogen. If it's at 1000 miles, 500 miles, or 300 miles, or 100 miles, and that all depends on the cost ratio of the two, and hydrogen being significantly cheaper than battery.