Challenges of being a learner between 30-39

What are challenges that people face between 30-39? Some of the challenges I believe occur are the issues within our actual careers. In example, school districts want teachers to be highly qualifies and strongly certified. The higher the education the better. However, they only pay teachers an additional $2,500 per year for having a Master's Degree and $5,000 roughly for a Doctoral. So if you pursue a Doctoral degree and have excessive student loans, well it will take you probably a lifetime of working within a school district to pay them all back. How then do we keep qualified educators? Pay them more?