It is not Tendulkar's fault he debuted at 16 while Lara did only at 20-21, if you take out those 16-20 years, Tendulkar's stats are even better.
But that is not the point.
Nobody asked Lara to retire. He realised he didnt have enough in his tank to continue after 2007.
Lara's last year was pretty mediocre to be honest. He was actually dire for most part of it, till the series in Pakistan happened, and Lara made lots of runs
against pathetic attack on flatbeds. The Pakistani attack comprised of luminaries like Umar Gul, Shahid Nazir, Kaneria and Abdul Razzak as 3rd seamer option lol! You had Mohammad Hafeez and Shoiab malik as second and third spinners and one get the idea how good that bowling attack was.