I ask myself something quite similar but coming from a different place (so to say).
How can I practice detachment (buddhism inspired letting go) while simultaneously accomplishing goals?
I ask myself this because I see a relation between holding on (firmly grasping a goal; the opposite of detachment) and the perseverance of success at doing difficult things.
In my own experience it remains a fact that if I hold on on to something tightly, this is why I suffer (painful); there's a truth behind "no pain no gain". However this is quite close to "them who don't try don't fail"... so they don't suffer BUT do not really accomplish anything either.
Finally, I don't consider the ego to be inherently bad, it's a tool. IMO a problem with it is that one's self is not the only one capable of using one's ego (e.g. we all have been manipulated by someone else).