This is AI Frontiers. Today, the AI stack is a trust and you are a tenant. The most important fact about AI competition is also the least discussed. The market is not merely becoming concentrated, it is being built to resemble the old trust structure, where control sits upstream in the infrastructure and downstream actors operate on terms set by a small number of gatekeepers. Here is the number that anchors the argument. Per Synergy Research Group data for the first quarter of 2026, Amazon Web Services, Microsoft Azure, and Google Cloud together hold 63% of the worldwide cloud infrastructure market, 28%, 21%, and 14% respectively, in a market that reached $129 billion in a single quarter and is growing 35% year on year. Cloud and high-performance compute are the industrial base of AI. If access to that base is concentrated, every downstream market inherits the concentration. The historical parallel is deliberate. By 1880, Standard Oil controlled the refining of 90 to 95% of all oil produced in the United States. It organized itself as a trust in 1882 and was dissolved by the Supreme Court in 1911 under the Sherman Act. Senator John Sherman put the principle plainly. If we will not endure a king as a political power, we should not endure a king over the production, transportation, and sale of any of the necessaries of life. The object has changed from rail, oil, and steel to compute, data, and model access. The logic of concentrated control has not. The mechanism working today is subsidy. Cheap credits, below cost access, and generous onboarding terms are framed as market expansion. In concentrated infrastructure markets, subsidy can also be a device for absorbing demand before full pricing power arrives. A cheap application programming interface today can become a pricing or contractual lever tomorrow. Zero price access can conceal dependency. Three consequences follow. Infrastructure ownership matters more than model performance. Whoever controls compute and deployment conditions sets the practical limits of competition. Labor's position weakens when upstream control hardens. If the bottleneck sits in a few firms, the gains do not spread widely. And application builders become tenants. They pay for access, depend on changing terms, and inherit strategic risk from suppliers they cannot discipline. The central question is not who has the slickest interface, it is who owns the bottleneck. For operators and mid sized firms, the immediate risk is overcommitting to a single stack because the short run pricing looks attractive. If one supplier controls your margin, your roadmap, and your customer access, you do not have an AI strategy. You have an exposure. That's AI frontiers.