Default AssumptionWide moat

The sum of the ecosystem is that Nvidia has become the default assumption of an entire field — PyTorch, the dominant research framework, ships with CUDA as its first-class backend¹ — the thing every new project starts with unless someone makes a deliberate and costly decision to do otherwise. That default is the most valuable position in any market, because it means Nvidia wins not by persuading anyone but by being the path no one has to think about; the burden of justification falls entirely on the alternative.

A default is powerful because inertia does the selling. When Nvidia is the assumed choice, a rival must not merely be as good but conspicuously, decisively better to overcome the effort and risk of departing from what everyone else does — and 'as good' is not enough to move a buyer off a default. The incumbent assumption wins all the ties, and in a fast-moving field most decisions are ties made under time pressure.

The default also reinforces itself through everyone else's defaults. Because the field assumes Nvidia, the tools assume it, the tutorials assume it, the job listings ask for it, and the safe, defensible choice for any individual is to go along — so the default is held in place not by Nvidia alone but by the collective expectation of the whole community, which is far harder to move than any one mind.

For the owner, being the default assumption is the widest expression of the ecosystem moat, because it converts every other advantage — the frameworks, the training, the tooling — into a single, self-sustaining fact: Nvidia is what you use unless you have a strong reason not to. Dislodging that requires not winning an argument but reversing an assumption held by an entire profession, and assumptions of that kind change very slowly indeed.