Through perseverance, Alvarado got his foot in the door. Once there, he established himself as an NBA player by doing the same things he did in college, by simply making things happen through force of competitive will. He just needed a chance to show that his attributes translated from the college to the pro game. I think he has successfully done that. Isn't clear that he brings marketable assets to an NBA team?
BTW, for those old enough to remember, there was considerable chatter that Mark Price was too small and too slow to play in the NBA prior to the draft. He was considered by most to be a fringe NBA prospect. But Price did get drafted at the top of the 2nd round. Same deal though, he got the chance and proved he could play.
But to the NBA teams' credit, they did give them a chance. Having doubts is not the same as not giving them a chance. The pelicans have gave Alvarado a chance and now Alvarado will likely have an NBA career as a consequence.