Hi Divya, the reason why it might appear it’s getting tougher to get in is because there are more students applying as the program grows in popularity. Moreover, the program was closed for most part of last year as they redesigned the application process to ensure a better experience for the applicants and a better quality of the program steps.
Moreover, there is no limit on the number of higher education instutions that can be part of the program and have a campus expert, however, you are limited to an expert per university at one time, with very few exceptions.
You can read more about the new program redesign on the blog (Introducing the New (and Improved!) Campus Experts Program - The GitHub Blog) and the application period is now open. However, unlike before, the program will only be accepting applications twice a year to make sure the students get the best experience in the process.
If you have any concerns and want to ask something specific you should message the program team on Campus Program - GitHub Support. Hope this helps and clarifies some of the things you mentioned