I don't know about IIM and AIIMS, but IIT students are quite lazy, however smart they are! So, even if your premise were true, your question has been answered.
Smartness and sluggishness are not correlated in a way most people expect. Sometimes, if you are smart then you can get results without hard work in school, but in real world, you have to put in the time.
You are affected by your peers. So, when you see laziness all around you and try to change it you will meet so much opposition. You will try for a few months or a few years and it becomes too draining and you just give up and become like them.