Firstly, KVPY is not the entrance exam of IISc Bangalore but a scholarship examination for students. IISc Bangalore itself does not have any admission test and admissions are given to top rankers in entrance exams like KVPY, JEE, and NEET. So everyone getting a KVPY scholarship is not offered admission to IISc.
One of my friends gave the KVPY exam in 2013–14 for the SA stream. In her selection letter, it was mentioned that 1,05,000 had written the KVPY exam for all streams. Today, it has gained more fame so the figures are expected to be at 1,20,000 and 1,50,000.
However, I don’t think you should be worrying about that yet because the selections are not limited to a specific number and keep increasing with the increase in those appearing for the exam. So, everyone who deserves this scholarship does get it.