The fight splits: scale-out stays pluggable-dominated (Marvell CEO), protecting transceiver suppliers. Scale-up is where chiplets contest copper — Marvell, NVIDIA, Broadcom collide. Three pre-registered signals resolve it: design-win concentration on partner rosters; silicon-photonics startups bought by hyperscalers not merchants (breaking open-platform thesis); or adoption stalls with hyperscalers on pluggables into 2028. Every scorecard stays provisional until one fires.