Of course, this article isn't meant to be a complete explanation of religion. I'm just highlighting a relatively neglected factor, the impact of the desert metaphor on the characterization of the monotheist's God.

But yes, you've suggested how the different explanations can be reconciled. The desert metaphor is hardly the only influence on religion. Polytheism is backed by the need to project anthropocentrism (social divisions) onto nature to feel at home in the alien world. That powerful incentive makes polytheism a religious default. Monotheism and nondual mysticism are more elite, enlightened notions, based on entheogens or reforms such as the interest in simplifying a canon or pantheon.

The desert metaphor helps account for the represented character of the resulting deity.

There are deserts in the Americas, but they're not pervasive like in the Middle East. North and South Americas have more mixed climates, so the desert metaphor wouldn't have been as pressing in those regions.

I doubt the esoteric core of monotheistic and monistic religions is identical. The scriptures and theologies are written poetically and abstractly so they can be interpreted in different ways. An inflexible religion won't survive as long as a flexible one. And monotheism is hardly the same as monism. Either God is identical with nature or he's not.