Because of its anonymous nature, then you can not trace the identity of the sender and receiver bitcoin. Well, that's what makes bitcoin become the most popular digital currency in the deep web.
But there will be ways how to make transactions can be in search and view. I think it can be done

This will be realized if a country has inaugurate or legalized bitcoin, the transaction can be monitored even though every day many people do a lot of transactions. I really agree with you, there will be technology that can track all that.