Hi, since I see the numbers of suttas Buddhaghosa mentioned. It seems more clear that what we have now is what was used the mostly in the oral chanting in Sri Lanka and that’s why only those was remembered. But there must have been ignored monastic chanting suttas written down only. And the Tripitaka when it was lost probably after Buddhaghosa or he was even mentioning more suttas because commentaries was saying there was more. Probably in his time already these suttas he mentioned was already lost. The amount of discourses missing is so much that it’s impossible to think we know Buddhism.
SuttaCentral