I've seen loads of third lane hoggers.
Subject to conditions I like to overtake them and cut across their nose from lane 4 to lane 1 to watch their, if any, reaction. It sometimes causes a change but often just from 3 to 2.
I do the same , a safe but exaggerated demonstration ,but many remain oblivious of their own failing and ,if they notice other vehicles at all, probably think me an idiot.
Just the tip of the iceberg I think. Many learners pass their test long before they are fully confident as drivers. While some continue to build on their skills and confidence through practice others give in to the temptation to minimise the situations they find stressful, such as lane changing, or indeed driving at all.Life long nervous and reluctant drivers. . (My mum passed her test late in life , but rarely drove thereafter. She too easily gave in to the temptation of leaving it to dad. )