Tier 0 requires an anchor network with enough category diversity that it cannot be characterized, contained or bought. Assembling that from scratch takes years. One ecosystem already is it.
Each stop is a page in the graph. The order is an argument — but every one of them is also a door into the rest of it, so you can leave the path wherever it stops being useful.
It is the only single commitment identified that activates all six adoption cascades simultaneously — and because the cascades are independent, joint activation is categorically rather than additively more likely to reach critical mass.