As wiki states under Thermolysis water heated to around 2500 C will break the bonds of H20 into H2 and O2.
If you reached this temperature instantly would the H2O just change into a gas (that would look like thin air) and could the H2 be extracted and cooled out to some storage unit, like a compressor if you were using something like tungsten pipes and tanks?
What would happen to H2 at such temperatures?
Seems like it should be achievable but since no one is doing it on at least a small production level it must not be?