When a single crab is put into a lidless bucket, they surely can and will escape. However, when more than one share a bucket, none can get out. If one crab elevates themself above all, the others will grab this crab and drag’em back down to share the mutual fate of the rest of the group.
Crab bucket syndrome is often used to describe social situations where one person is trying to better themself and others in the community attempt to pull them back down.