He can stay at ECU forever and have a legacy type career at his alma mater in a pretty weak baseball conference where they wont face many challenges.
BUT he only makes like $600k per year at ECU. He could go to OM and literally quadruple his salary.
At OM, he would face much tougher competition and would be introduced to the possibility of being fired if he didn't live up to expectations.

So 1) take the easy route and become a legend at your alma mater or 2) take the harder router and become a very very rich man.