Why is IIT so popular in india?
1. Toughness of entrance exam
If you search toughest exams of the world (not India), every website mentions JEE in top 10. And toughness of JEE is basically toughness of JEE-Advanced. Mains exams which is used as a screening test for IIT is not remarkably tough. It is tough because of high cut-offs and large number of students appearing, but not tough as in difficulty level of questions. Questions are never directly repeated in Advanced exam and you don't have something called question bank. Syllabus includes all concepts of physics, chemistry and maths until undergraduate level and questions in the exam require understanding of concepts, careful thinking and mental concentration. I told you to skip this.
Even for job of professors, the recruitment is very tough and requires minimum of PhD Degree. But today, many other engineering colleges have such strict measures.
Okay, so I have three options, Science, Commerce and Humanities. I don't want to crack civil services, other professions in Humanities are risky. (or creative, same thing actually). Medical- I can't study for 10 years, I don't have interest in medical. Aur seat bhi nhi milti, yaar. Other creative professions like genetics and microbiology are not well established in India. So, commerce, hmm.. I have this stupid belief that those who are better at studies go for science and commerce is for average students. So, I got cgpa 10 in 10th, I am good student, I will take non-medical, engineering seems good, just 4 years of study and assured job, oh there's IIT, I will become a superstar if i get into IIT..I will crack it...
Story of 13 lakhs every year...
3. Media Hypes
"xyz of IIT bombay bags 1.6 crore package at Google..."
News doesn't stress that only one out of so many students was able to get that and how much he worked hard. Media shows it like an overnight success. And student of another college who works hard, get an avearge placement, still works hard, gets promotion and increments and finally reaches at a top MNC doesn't make it to the news.
4. Old and established university
Ok so "are there any other useful universities"
This is laughable question, IIITs, top NITs, NSIT, DTU are equally good engineering colleges which only lack in brand name equal to IIT, and partially lack in student quality. Partially because not all IITians are top minds of country, some come under reserved category.
Other than engineering colleges, there are definitely other "useful universities" of pure science, commerce, and arts.
Plus, colleges which don't have reputed name can't be discarded as "not useful", student can work hard to achieve success, as the Google CEO. Check out stats of top MNC, 50% of employees are not from reputed colleges, check faculty at IITs, half of them did not graduated from IIT.
Reputation and Placement:
One of the main reason parents encourage, or should we say push, children to pursue admissions into IIT is because of the reputation that these premier institutions carries around the world and that the top companies fight each other to recruit top talents out of IIT. For past several years, key departments, engineering mainly, in IITs have boosted 100% placements, which means you will have a lucrative job offer in hand before you graduate. That's pretty cool, isn't it?
If above sounds interesting and make you want to join premier institution like IIT, first step would be to join a coaching. While one may be able to prepare by herself/himself, best thing to do will be join online / physical classroom coaching which will help you train faster and make you think critically.