Take Ebay for Example there is no Default trust list.....Your worthiness is based upon your successful transactions not because the creator says these people should be trusted.
You're 100% mistaken.
There is a default trust list with Ebay.
It encompasses all users of Ebay.
If it weren't for a default seed of trust, any trust network would be utterly useless.
The reasons why we can't just include all users in the default trust seed of bitcointalk are obvious and have been discussed at length.
I disagree. Ebay users have earned their trust ratings through selling and buying transactions. they were not given their ratings by default.