Ebay probably had a massive marketing budget and a focus region. Shipping of physical goods won't thrive on 12 nostriches wanting it into existence.
I want amazon, ebay, mercadolibre and all their clones to become obsolete due to one "trade net" and maybe we can build it on nostr but so far I don't see it happening.
For example Amazon appears to have some anti-competitive practices. So even though they take a cut, they don't allow the merchants to sell their products cheaper elsewhere and as that's not allowed in Europe, they don't remove them from the platform but make buying more cumbersome. So in essence, merchants get punished for *also* selling on our nostr thing and so merchants just stick to trying to be big on Amazon.