Why it is continuously hard for IIM A, B, C, XLRI to compete with ISB in executive program in spite of it being just 15 years old?

One of my friends at ISB claims that the main reason for ISB Hyderabad to hold the top position in the executive program over the years. It is its core competency rather than just competing with institutes like IIMs and XLRI, who lead in the 2-year MBA and PGDM programs. 

The points below provide a brief overview of the success story of ISB Hyderabad.

• ISB Hyderabad has been developing with a work experience of above two years at least. 
• Due to the shorter time span of the executive program, it is more popular and in demand. 
• In the traditional MBA program, the curriculum is an extension to the undergraduate program, emphasizing mostly classroom learning. 
• ISB Hyderabad has somewhat established a cheaper alternative to the so-called American MBA system. 
• There are collaborations with companies like Kellogg’s, which helped in fulfilling the demand for a world-class MBA degree.
• They have a lot of contribution in its breaking into the Indian executive MBA program market. 
• It has resulted in a program that is half-priced as the American MBA programs. 
• The program in ISB is just 11 months, as opposed to the 24 months MBA program from other institutes.
• For fresh graduates, IIMs are always the first priority, which offers a standard 2-years MBA degree. The core competency of IIMs is to train the less experienced students. But, in the last few years, IIMs are getting into the executive programs in MBA, but those are treated under the non-core segment.

Although ISB charges twice as much as IIMs at present times, it has been the first choice for working professionals for the reasons stated above. The core competency of ISB discussed above makes it the clear winner in executive education, which the IIMs and XLRI cannot defeat.