The money makers are investing while the Governments are herding the folk
laws will probably come in, where homemade units will be illegal or require heavy engineering testing and licenses + fees, but still it proves to the committed nay-sayers that H2 is a fuel source.
https://interestingengineering.com/innovation/worlds-largest-electrolyzer-has-the-shape-of-screwdriver
Less complicated :
https://www.sciencedirect.com/science/article/abs/pii/S2352492823003513