He will never become one, because instead of following the only path that leads to some success, the path of commitment, of determination, of a strong will for an improvement, he chose to walk the cutoff to failure, the one of excuses. A skilled spearfisherman can, and usually does, catch nice fish where other do not even see one. And not because of a miracle or sheer good luck. Or because he's six legged or four lunged. Admitting this means that one can improve if he wants to. Ascribing other spear's catches to good luck or heavenly spots unknown to other, means giving up any improvement.
If you want to become a good spearfisherman, be curious! Watch carefully everything that's happening around you. When you clean out a fish after a catch, check what it ate. Take mental notice of all the details of the catch that can be meaningful, the water temperature, the time of the year, the time of the day, the current, the tide. When at the port, look at what professional fishermen have caught inside their gill nets, check if bait fix is swimming everywhere or if it's not present at all.. Try to build relations between the things you observed, like the movement of bait fish when the predatore was approaching, the kind of rock that fish eventually slipped below after discarding a dozen of similar ones.... When the time is right, some of the odds will narrow, and everything will look clearer, even if only for a while, due to the ever changing nature of a world made of living creatures, due to the law of constant change.
A spearfisherman who's not curious is bound to be left behind, or to never become a real spearfisherman at all.