Hydrogen-based technology was not mature in 2008, and needed more time to undergo further efficiency improvements and cost reductions. During the past decade, significant financial resources have been spent on hydrogen energy research and development globally, allowing hydrogen to make a spectacular comeback. This time, it’s here to stay.
Source: https://www.weforum.org/agenda/2019/04/why-don-t-the-public-see-hydrogen-as-a-safe-energy-source/