Why don’t you turn off the PageRank feature in the Google Toolbar?

Why don't you turn off the PageRank feature in the Google Toolbar?

Why don’t you switch off the PageRank Toolbar feature? It is widely used by link sellers as a link grading system. Why do you continue to display PageRank publicly? It appears to have little relevance, except to spammers.
Danielroofer (aka Daniel Weadley), Camberley, Surrey, UK