This is all high level, and rests on many assumptions. For example, natural gas costs increased by a factor of 10 during Russia’s invasion of Europe. In such circumstances, methane from the air becomes extremely cheap in comparison.
Not only that, but given the political climate, countries might decide to pay a premium for methane from the air vs from the ground, if the ground methane comes from Russia or similarly hostile countries.
This is one of the reasons why the US approved the Inflation Reduction Act (IRA), which is so generous that, in some parts of the US, this air-to-gas system would already break even after a few years.
Of course, this would probably be more true in Arizona than in Vermont, since the Sun shines stronger there. Which illustrates yet another varying condition.
The Sun shines more strongly in countries near the equator, which tend to be poorer¹¹. This means they can obtain solar electricity—and methane—for cheaper. However, since most countries farther from the equator get as much as 50% of the solar irradiation of warmer countries, and solar panel costs generally drop by 12% per year, it will only take about five additional years for the same economics to apply there.
This means the breakeven point between methane from the ground and from the air will arrive at different times in different places. What matters is that it arrives somewhere soon, so we can get this process going as fast as possible. And as we saw, it’s already cheaper in some parts of the US than others.
What this means is that the right company figuring out how to efficiently produce methane from the air can already replace traditional fossil fuel companies in the US by selling their product more cheaply.