By and large, ND's major "disadvantage' in recruiting is it is primarily a 4 year school with virtually the highest graduation rate year in and year our. The graduation rate says it all. Unless ND changes it's mission in this regard, you aren't going to see any 25 man classes for ND.
Also, ND only rarely will force kids to leave because they haven't performed "up to expectations." An ND kid who doesn't stays and graduates.
Other schools chase kids off all the time.
There is also the factor of guys moving on to the pros which is definitely an advantage of success. Gray shirting, another thing that ND doesn't do, also is a major advantage. But that isn't nearly as big a factor as kids being pushed out by their programs.
All it takes is about 5 kids to leave each year and you get an extra 20 kids every 4 years.