In oxygenated tropical waters, wood does not survive. The shipworm bores through hulls, reducing entire fleets to dust within decades. This creates a forensic bias: we only find the "Spikes"—the rare wrecks preserved by catastrophic events that buried them instantly in anoxic mud.
The absence of BC-era wrecks is not proof that trade didn't exist; it is proof that the biological "recycling" mechanism of the ocean is efficient.
To find the truth, we must look for the "Cairn Ships"—vessels that sank into low-oxygen silt pockets near river deltas (e.g., the Tana or Pearl River).
Long before the Silk Road, the "Sewn-Plank" technology of the Austronesians linked the Philippines to India and the Horn of Africa (1st Millennium BC).
This was a "Water-State"—a territory defined by the immutable physics of the Monsoon winds rather than the fickle borders of kings. It was stable, persistent, and largely peaceful.
CONCLUSION: We are looking at a history of "Families having Dinner" that spanned 4,000 years. The shipworm ate the table, but the isotopic traces of the food remain in the soil.