...tell ya what, you go run a 2:15:00 marathon. It will be then you have the room to make a negative comment like that. I've run a 2:19 and I can tell you that a 2:15:00 marathon takes immense competitiveness and focus to achieve. "Competitive at a high level" is exactly what a 2:15:00 marathon is.
No, it's ability. If you're training at your utmost ability and he's training at his, he's beating you because he's got more ability, not because he's trying harder. Think talent. And I don't believe you are a 2:19 marathoner, hardly.
Running 2:15 is great but unfortunately it won't get anything or very little financially in the big races. You can win smaller marathons, but there's very little to zero prize money in those races.
Decent runner for sure, but unfortunately in 2018 he's in no man's land.