Island vs. mainland evolution is probably an apt comparison.

On a mainland (a region with widespread intercommunication within a species), speciation is relatively rare (baring catastrophic events). On an island, any given mutation is proportionately a larger share of the genome already, and has an opportunity to take hold even if there is little or no relative advantage.

(Evolution is a case of natural selection, with the presumption being that that selection is itself beneficial. In truth, "benefit" can be wide-ranging, and genetic drift where a set of equipotent or merely latent advantages occur and are distributed are frequent. There's also the distinction between what I call exogenous and endogenous selectors. The former are imposed by the environment, the latter from within the social behaviour of the species itself (assuming social behaviours). There are also purely random events --- getting hit by an asteroid or consumed by a volcano, say --- though one might argue that vigelance plays a role here.)

But yes, a globally-interconnected world with common trade interests, exchange, languages, etc., is one that's been flattened and made uniform. One suspects that disuniformities may eventually appear and change the economic calculus.

One force that seems highly potent at present, and underappreciated, is the reliance on energy (oil) and strategic minerals, both either only or highly preferentially accessible in specific locations. My view of the post-WWII global dynamic is that it makes far more sense to consider it as an interplay between three major oil-producing regions: the Soviet bloc which was both a largely self-sufficient producer (Baku) and exporter, the Western bloc (NATO, ASEAN, Japan, South Korea) which was a major producer, but relied increasingly on imports, and the swing bloc of the OPEC states (notably Saudi Arabia, though also Iran, Libya, Iraq, smaller Gulf states, and others). The US/NATO posture of protecting and defending global oil production and transport emerges in this context. The Soviet bloc could rely on land-based pipeline transport to a far greater extent.

Strategic minerals, largely derived from Africa, spell out much the rest of this story.

There's more explanation in this to my mind than many of the ideological explanations. My sense is that ideology itself more likely flows from the geopolitical dynamics.

As relates to future geopolitics: the general sense is that oil will diminish in signficance (probably, though not certainly). But an advanced electrified world relies increasingly on exotic elements either not widely available (e.g., coltan), or which, whilst not rare per se, have exceedingly messy extraction processes (the so-called "rare earths", actually reasonably abundant but not ore-forming, meaning that even "rich" deposits are actually low concentrations, requiring much overburden removal, processing, and tailings.

Lithium already appears poised to be the next energy storage medium, and is similarly to oil nonuniformly distributed globally. Seawater extraction seems one possible way around that limitation, though at 1ppm concentrations, that's a challenge. Possibly if integrated with other seawater-based activities (desalination, seawater-based fuel synthesis, etc.).