I'm in the same boat!
I thought all dogs love to fetch, but Rumo would watch the ball / frisbee go and be like, "meh."
He is getting slightly better...
1. I make fun noises and wave the ball around and get him all excited, before I throw it.
2. Instead of throwing it long and low, I throw it in an arc more up in the air, closer to him, so he can kind of leap up and then pounce on it
Then he runs around with a bit with the ball in his mouth, and eventually zooms near me and drops it in my vicinity (if he wants to play again)
But our maximum repetitions is maybe....5? 5 is a really good day.
I know we are done when he gets the ball, takes it to a shady patch of the yard, and lies down with it. Done.
Fetch will never be his favorite thing. :-(
My neighbor has a golden retriever who is a really focused Fetcher.
She can be offleash in her street and she will ALWAYS bring the ball right back at a full gallop...
I know my neighbor, and he is a fairly casual dog owner (not like he's trained her a ton).
So maybe there is something in the breeding...
even if I trained Rumo a lot to really retrieve, I think he would never do it with such joy!