Despite what Elon Musk says, fuel cells aren't dead in the slightest. Yes there has been some stagnation in innovation from the major players, buy there has also been some significant and ground breaking improvements in fuel cell efficiency in the past few years.

At least one company that I know of, Loop Energy, has proven (independently verified) fuel cell tech that will soon make cargo trucks 0-emissions. (Note: My brother was the lead engineer and basically developed this)

https://loopenergy.com/

Sure it has taken a while, but things like this would not have been possible without that initial investment in fuel cells.