It seems feasible - the technology components to build a platform like this exist, and the sub-problems (community-building, trust/spam, peer review and consens

It seems feasible - the technology components to build a platform like this exist, and the sub-problems (community-building, trust/spam, peer review and consensus, supply chain analysis, and so on) have been researched and developed into large-scale production systems. Bringing the pieces together in a robust and scalable way that results in an effective, simple and collaborative product is the challenge. It's potentially more a question of motivation, persistence and focus than technology. As for whether the timing is right for it to succeed - I don't know: Some people might not want or find it easy to follow even the best-intended guidance a platform like this could provide, for example if they're bound by local economic or cultural habits and constraints. That could lead to social rifts ("we can't make these changes" vs "those people won't make the changes") which risks creating undesirable conflict.