First of all, the quality of an institute can’t be assessed by the number of selections in GSoC and ACM ICPC from it. Indian colleges provide no special training for GSoC. The selections are completely based on the efforts and skills of students.
My friend from the Manipal Institute of Technology got selected for GSoC a few years back. He did it in his first year itself. There were others in his batch who would’ve gotten selected had they applied.
Now the reasons for a low participation rate in GSoC may be as under-
As for ACM-ICPC, the teams from Manipal do make it to the on-site. However, the selection rate is low because of poor strategy and poor planning. The teams are unbalanced as well.
Manipal has a good programming culture. There are weekly Code Meets where students meet up and discuss random algorithms and problem-solving techniques, past questions from competitions like ACM-ICPC, and general questions from SPOJ. Clubs like IE CSE, IEEE Manipal, and ISTE host coding competitions throughout the year. Manipal hosts dedicated tech fests for coding and computers.
Even though Manipal doesn’t perform too well in GSoC and ICPC, the students are making constant efforts to improve in that direction. Also, this is an irrelevant criterion for judging the quality of education in an institution.