"Will economies of scale of hydrogen production render gas...

"Will economies of scale of hydrogen production render gas obslete incorporating cost relativities by the end of this decade? Any guesstimates on timelines?" End of this decade? Almost zero chance gas will be obsolete. Will take another couple of decades to phase out.

I advise you to run your own maths/calculations to see the facts about what can/cannot be replaced by Hydrogen.

Oil is more expensive than, so oil will be mostly replaced before gas.
Gas blending with hydrogen will begin by the end of the decade.
Natural Gas became more expensive than hydrogen during the start of the Russia Ukraine war, but they've since come back down. Its unlikely to be considerably cheaper any time soon.
So for long term replacement of NG with H2 to be successful, there needs to be a carbon tax or political legislation or social will to go green.