History of migration in Kottayam and Pathanamthitta

Just recently visited Pathanamthitta. Was shocked to see that very few youngsters are there in the district. Everywhere I went it was mostly middle aged or old people. Did meet a few youngsters but they too are moving away from Pathanamthitta. Is it that bad to live in Pathanamthitta cause there are many facilities nowadays and institutions that are top quality be it schools or hospitals. Yes work opportunities are less but work opportunities are also less in Kannur, kollam, Malappuram, Kasaragod, Trissur but yet the amount of migration from Pathanamthitta and to an extent Kottayam is faster compared to the other districts. Is it just the culture among the malayali christians in these districts to migrate out of Kerala and India just like the punjabis, telugu and Gujaratis in India. Most of the malayali christians outside India are also from Kottayam and Pathanamthitta. In my understanding this migration has been happening since so many decades so I wanted to know more about this migration trend and why is the case for Pathanamthitta and Kottayam like this interms of demographic collapse.