winning X titles - is not the only way to become a great..
winning a career grandslam would be another (only 7 men to ever do this)
or even a golden grand slam, (only 2 men)
Both could be achieved within 2-3 years of murray still being fit/healthy..
now im not saying he will, - infact its hugely unlikely..
But..
Not impossible as some people here seem to suggest..