This geopolitical model predates modern energy dynamics; in any case, Siberian minerals will flow to Chinese and European factories for a long time to come. This model also doesn’t require American dominance. (Again, it dates from the age of British and Austro/Russo/French power.) A future Leviathan could operate with Europe and America on co-equal footing, versus the D.C. dominance we see today.
As for land transport becoming more efficient than ocean, that’s a pipe dream. We’re talking about orders of magnitude of cost difference between the cutting edge of where rail/loop could be in a decade and where an inefficient shipping industry is today. Rail is also less resilient in times of war, as we’re seeing with Russia, being more targetable (Ukraine) and deniable by intermediaries (Kalingrad).
The real tipping point in favour of the Leviathan, however, comes with air forces and missiles, force projection options which didn’t exist when the model was conceived. Xi’s strategic fuckup has been in failing to see that China, too, could command a Leviathan. In an alternate timeline, a patient and thoughtful China is signing trade deals and security compacts with the Philippines, Vietnam, Indonesia Korea and maybe even Taiwan and Japan. Instead, Beijing Bethemothed the islands which encircle China into an adversarial stance, a stance they can maintain thanks to the stopping power of water, and a position which prevents China from projecting blue ocean naval power.