Why have trust networks not taken hold?

Many years ago I learned the basics of trust networks and I truly think that they may be one way to help sort the wheat from the chaff.

Why a "like/dislike" button, when a "trust/no trust" (with scale) could be better utilized.

Each person could then be in charge of their own filter bubble in choosing the people that they "trust" which gives more weight to their influence. Not that it woudn't be possible to game the system, but It would probably be better than what we have, all these "facts" thrown around with no way to know what other people truly believe.