It's worth reflecting on the fact that for most of human history, sea travel is easier and faster than land travel. That's one of the main reasons why major towns and cities are centered on river access.
do you know how far madagascar is from easter island? if you're talking about mediterranean and river travel, yes you're right. but the pacific ocean + indian ocean are utterly massive.
I believe more trade between China and the Mediterranean was transited via Indian Ocean trade routes than via the traditional Silk Road, though I'm hard-pressed to find actual statistics.